Remote Desktop disconnected or can’t connect to remote computer or to Remote Desktop server (Terminal Server) that is running Windows Server 2008 R2

Introduction:
This article attempts to guide you through understanding the most common settings that affect establishing a Remote Desktop session in an enterprise environment.


Note: 

Remote Desktop Server

Troubleshooting Establishing a Remote Desktop

Symptoms:

1. You may be limited in the number of users who can connect simultaneously to a Remote Desktop session or Remote Desktop Services session

Limited number of RDP connections can be due to misconfigured Group Policy or RDP-Tcp properties in Remote Desktop Services Configuration, by default, the connection is configured to allow an unlimited number of sessions to connect to the server. When you try to make a Remote Desktop Connection (RDC) you get the following error:

To verify that Remote Desktop is enabled:

1. Start the System tool. To start the System tool, click Start > Control Panel > System Icon and then click OK.
2. Under Control Panel Home, click Remote settings.
3. Click the Remote tab. Under Remote Desktop, Select either option depending on your security requirements:
   
   • Allow connections from computers from computers running any version of Remote Desktop (less secure)
   • Allow connections from computers only from computers running Remote Desktop with Network Level Authentication (more secure)

If you select “don’t allow connections to this computer” on the Remote tab, no users will be able to connect remotely to this computer, even if they are members of the Remote Desktop Users group.

To verify Remote Desktop Services "Limit number of connections" Policy

1. Start the Group Policy snap-in, open the Local Security Policy or the appropriate Group Policy
2. Navigate to the following location:
   Local Computer Policy > Computer Configuration>Administrative Templates > Windows Components > Remote Desktop Services> Remote Desktop Session Host> Connections "Limit number of connections"
3. Click “Enabled”
4. In the RD Maximum Connections allowed box, type the maximum number of connections you want to allow, and then click OK.

To verify Remote Desktop Services RDP-Tcp properties

Depending on the version of your operating system, please follow the steps below:

Setting via Remote Desktop Services Configuration

To configure the number of simultaneous remote connections allowed for a connection

1. On the RD Session Host server, open Remote Desktop Session Host Configuration. To open Remote Desktop Session Host Configuration, click Start, point to Administrative Tools, point to Remote Desktop Services.
2. Under Connections, right-click the name of the connection, and then click Properties.
3. On the Network Adapter tab, click Maximum connections, enter the number of simultaneous remote connections that you want to allow for the connection, and then click OK.
4. If the Maximum connections option is selected and dimmed, the Limit number of connections Group Policy setting has been enabled and has been applied to the RD Session Host server.

To verify Remote Desktop Services Logon rights:
Configure the Remote Desktop Users Group

The Remote Desktop Users group on an RD Session Host server is used to give users and groups permission to remotely connect to an RD Session Host server.

You can add users and groups to the Remote Desktop Users group in the following ways:

• Local Users and Groups snap-in
• On the Remote tab in the System Properties dialog box on an RD Session Host server
• Active Directory Users and Computers snap-in, if the RD Session Host server is installed on a domain controller

You can use the following procedure to add users and groups to the Remote Desktop Users group by using the Remote tab in the System Properties dialog box on an RD Session Host server.

Membership in the local Administrators group, or equivalent, on the RD Session Host server that you plan to configure, is the minimum required to complete this procedure.

To add users and groups to the Remote Desktop Users group by using the Remote tab

1. Start the System tool. To start the System tool, click Start > Control Panel > System Icon and then click OK.
2. ()
   Under Control Panel Home, click Remote settings.
3. In the System Properties dialog box, on the Remote tab, click Select Users. Add the users or groups that need to connect to the RD Session Host server by using Remote Desktop. The users and groups that you add are added to the Remote Desktop Users group. 

If you select 'Don’t allow connections to this computer' on the Remote tab, no users will be able to connect remotely to this computer, even if they are members of the Remote Desktop Users group.  

To add users and groups to the Remote Desktop Users group by using Local Users and Groups snap-in:

1. Click Start > Administrative Tools, Open Computer Management.
2. In the console tree, click the Local Users and Groups node.
3. In the details pane, double-click the Groups folder.
4. Double-click Remote Desktop Users, and then click Add.
5. In the Select Users dialog box, click Locations to specify the search location.
6. Click Object Types to specify the types of objects you want to search for.
7. Type the name you want to add in the Enter the object names to select (examples) box.
8. Click Check Names.
9. When the name is located, click OK.

Notes:

• You can’t connect to a computer that's asleep or hibernating, so make sure the settings for sleep and hibernation on the remote computer are set to Never. (Hibernation isn't available on all computers.) For information about making those changes, see Change, create, or delete a power plan (scheme).
• You can't use Remote Desktop Connection to connect to a computer using Windows 7 Starter, Windows 7 Home Basic, or Windows 7 Home Premium.
• Members of the local Administrators group can connect even if they are not listed.

2. You may have a Port assignment conflict

This problem could indicate that another application on the Remote Desktop server is using the same TCP port as the Remote Desktop Protocol (RDP). The default port assigned to RDP is 3389.

To resolve this issue, determine which application is using the same port as RDP. If the port assignment for that application cannot be changed, change the port assigned to RDP by editing the registry. After editing the registry, you must restart the Remote Desktop Services service. After you restart the Remote Desktop Services service, you should confirm that the RDP port has been correctly changed.

Remote Desktop server Listener Availability

The listener component runs on the Remote Desktop server and is responsible for listening for and accepting new Remote Desktop Protocol (RDP) client connections, thereby allowing users to establish new remote sessions on the Remote Desktop server. There is a listener for each Remote Desktop Services connection that exists on the Remote Desktop server. Connections can be created and configured by using the Remote Desktop Services Configuration tool.


To perform these tasks, refer to the following sections.

Determine which application is using the same port as RDP

You can run the netstat tool to determine if port 3389 (or the assigned RDP port) is being used by another application on the Remote Desktop server.

To use netstat:

1. On the Remote Desktop server, click Start, click Run, type cmd, and then click OK.
2. At the command prompt, type netstat -a -o and then press ENTER.
3. Look for an entry for TCP port 3389 (or the assigned RDP port) with a status of Listening. This indicates another application is using this port. The PID (Process Identifier) of the process or service using that port appears under the PID column.

To determine which application is using port 3389 (or the assigned RDP port), use the tasklist command-line tool along with the PID information from the netstat tool.

1. On the Remote Desktop server, click Start, click Run, type cmd, and then click OK.
2. Type tasklist /svc and then press ENTER.
3. Look for an entry for the PID number that is associated with the port (from the netstat output). The services or processes associated with that PID will appear on the right.

Change the port assigned to RDP

You should determine if this application can use a different port. If you cannot change the application’s port, you will have to change the port assigned to RDP.

Important:  Microsoft does not recommend changing the port assigned to RDP.

If you have to change the port assigned to RDP, you must edit the registry.

To perform this procedure, you must have membership in the local Administrators group, or you must have been delegated the appropriate authority.

To change the port assigned to RDP:

Caution:  Incorrectly editing the registry might severely damage your system. Before making changes to the registry, you should back up any valued data.

1. On the Remote Desktop server, open Registry Editor. To open Registry Editor, click Start, click Run, type regedit, and then click OK.
2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
3. Locate and then click the following registry subkey:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Remote Desktop server\WinStations

Note:  RDP-TCP is the default connection name. To change the port for a specific connection on the Remote Desktop server, select the connection under the WinStations key.

1. In the right-pane, double-click the PortNumber registry entry.
2. Type the port number that you want to assign to RDP in the
3. Click OK to save the change, and then close Registry Editor.

Restart the Remote Desktop Services service

For the RDP port assignment change to take effect, stop and start the Remote Desktop Services service.

To perform this procedure, you must have membership in the local Administrators group, or you must have been delegated the appropriate authority.

To stop and start the Remote Desktop Services service:

1. On the Remote Desktop server, open the Services snap-in. To open the Services snap-in, click Start, point to Administrative Tools, and then click Services.
2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
3. In the Services pane, right-click Remote Desktop Services, and then click Restart.
4. If you are prompted about restarting other services, click Yes.
5. Confirm that the Status column for the Remote Desktop Services service displays Started.

Confirm that the RDP port has changed

To confirm that the RDP port assignment has been changed, use the netstat tool.

To use netstat:

1. On the Remote Desktop server, click Start, click Run, type cmd, and then click OK.
2. At the command prompt, type netstat -a then press ENTER.
3. Look for an entry for the port number that you assigned to RDP. The port should appear in the list and have a status of Listening.

Important:  Remote Desktop Connection and the Terminal server Web Client use port 3389, by default, to connect to a Remote Desktop server. If you change the RDP port on the Remote Desktop server, you will need to modify the port used by Remote Desktop Connection and the Remote Desktop server Web Client. For more information, see the following Microsoft Knowledge Base Articles:

• How to change Remote Desktop server’s listening port
  (http://go.microsoft.com/fwlink/?LinkId=102164)
• How to configure the Remote Desktop client to connect to a specific port when you use Windows XP
  (http://go.microsoft.com/fwlink/?LinkId=102165)
• How to change the Listening Port in the Windows Remote Desktop server Web Client
  (http://go.microsoft.com/fwlink/?LinkId=102166)

Verify

To verify that the listener on the Remote Desktop server is working properly, use any of the following methods.

Note:  RDP-TCP is the default connection name and 3389 is the default RDP port. Use the connection name and port number specific to your Remote Desktop server configuration.

Method one

Use an RDP client, such as Remote Desktop Connection, to establish a remote connection to the Remote Desktop server.

Method two

To use the qwinsta tool to view the listener status on the Remote Desktop server:

1. On the Remote Desktop server, click Start, click Run, type cmd, and then click OK.
2. At the command prompt, type qwinsta and then press ENTER.
3. The RDP-TCP session state should be Listen.

Method three

To use the netstat tool to view the listener status on the Remote Desktop server:

1. On the Remote Desktop server, click Start, click Run, type cmd, and then click OK.
2. At the command prompt, type netstat -a then press ENTER.
3. The entry for TCP port 3389 should be Listening.

Method four

To use the telnet tool to connect to the RDP port on the Remote Desktop server:

1. From another computer, click Start, click Run, type cmd, and then click OK.
2. At the command prompt, type telnet servername 3389, where servername is the name of the Remote Desktop server, and then press ENTER.

If telnet is successful, you will receive the telnet screen and a cursor.

If telnet is not successful, you will receive this error:

Connecting To servername...Could not open connection to the host, on port 3389: Connect failed

The qwinsta, netstat, and telnet tools are also included in Windows XP and Windows Server 2003. You can also download and use other troubleshooting tools, such as Portqry.



3. You may have an incorrectly configured Authentication and Encryption setting

Configuring authentication and encryption    

Use the following procedure to configure authentication and encryption for a connection.

1. On the RD Session Host server, open Remote Desktop Session Host Configuration. To open Remote Desktop Session Host Configuration, click Start, point to Administrative Tools, point to Remote Desktop Services, and then click Remote Desktop Session Host Configuration.
2. Under Connections, right-click the name of the connection, and then click Properties.
3. In the Properties dialog box for the connection, on the General tab, in Security layer, select a security method.
4. In Encryption level, click the level that you want. You can select Low, Client Compatible, High, or FIPS Compliant. See Step 4 above for Windows Server 2003 for Security layer and Encryption level options.

Note  

• To perform this procedure, you must be a member of the Administrators group on the local computer, or you must have been delegated the appropriate authority. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure.
• To open Remote Desktop Services Configuration, click Start, click Control Panel, double-click Administrative Tools, and then double-click Remote Desktop Services Configuration.
• Any encryption level settings that you configure in Group Policy override the configuration that you set by using the Remote Desktop Services Configuration tool. Also, if you enable the System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing
  (http://technet.microsoft.com/en-us/library/cc780081(WS.10).aspx)
  Group Policy setting, this setting overrides the Set client connection encryption level Group Policy setting.
• When you change the encryption level, the new encryption level takes effect the next time a user logs on. If you require multiple levels of encryption on one server, install multiple network adapters and configure each adapter separately.
• To verify that certificate has a corresponding private key, in Remote Desktop Services Configuration, right-click the connection for which you want to view the certificate, click the General tab, click Edit, click the certificate that you want to view, and then click View Certificate. At the bottom of the General tab, the statement, "You have a private key that corresponds to this certificate" should appear. You can also view this information by using the Certificates snap-in.
• The FIPS compliant setting (the System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing setting in Group Policy or the FIPS Compliant setting in Remote Desktop server Configuration) encrypts and decrypts data sent from the client to the server and from the server to the client, with the Federal Information Processing Standard (FIPS) 140-1 encryption algorithms, using Microsoft cryptographic modules. For more information, see FIPS 140 Evaluation
  (http://go.microsoft.com/fwlink/?LinkID=34627)
  (http://go.microsoft.com/fwlink/?LinkID=34627
  (http://go.microsoft.com/fwlink/?LinkID=34627)
  ).
• The High setting encrypts data sent from the client to the server and from the server to the client by using strong 128-bit encryption.
• The Client Compatible setting encrypts data sent between the client and the server at the maximum key strength supported by the client.
• The Low setting encrypts data sent from the client to the server using 56-bit encryption.

You cannot completely disconnect a Remote Desktop server connection

After a Remote Desktop server client loses the connection to a Remote Desktop server, the session on the Remote Desktop server may not transition to a disconnected state. Instead, it may remain active even though the client is physically disconnected from the Remote Desktop server. If the client logs back in to the same Remote Desktop server, a totally new session may be established, and the original session may still remain active.

To work around this issue, follow these steps:

1. Click Start, click Run, type gpedit.msc, and then click OK.
2. Expand Computer Configuration, expand Administrative Templates, expand Windows Components, expand Remote Desktop Services expand Remote Desktop Session Host and then click Connections.
3. In the right pane, double-click Configure keep-alive connection interval.
4. Click Enabled, and then click OK.
5. Close Group Policy Object Editor, click OK, and then quit Active Directory Users and Computers.

4. You may have a Certificate Corruption

Remote Desktop Services clients may be repeatedly denied access to the Remote Desktop server. If you are using a Remote Desktop Services client to log on to the Remote Desktop server, you may receive one of the following error messages:

Error message 1


Error message 2


Additionally, the following event ID messages may be logged in Event Viewer on the Remote Desktop server:

Event message 1

Event ID: 50

Event Source: TermDD

Event Description: The RDP protocol component X.244 detected an error in the protocol stream and has disconnected the client.

Event message 2

Event ID: 1088

Event Source: TermService

Event Description: The terminal services licensing grace period has expired and the service has not registered with a license server. A terminal services license server is required for continuous operation. A terminal server can operate without a license server for 90 days after initial start up.

Event message 3

Event ID: 1004

Event Source: TermService

Event Description: The terminal server cannot issue a client license.

Event message 4

Event ID: 1010

Event Source: TermService

Event Description: The terminal services could not locate a license server. Confirm that all license servers on the network are registered in WINS/DNS, accepting network requests, and the Terminal Services Licensing Service is running.

Event message 5

Event ID: 28

Event Source: TermServLicensing

Event Description: Terminal Services Licensing can only be run on Domain Controllers or Server in a Workgroup. See Terminal Server Licensing help topic for more information.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756  How to back up and restore the registry in Windows

To resolve this issue, back up and then remove the X509 Certificate registry keys, restart the computer, and then reactivate the Remote Desktop Services Licensing server. To do this, follow these steps.

NOTE: Perform the following procedure on each of the Remote Desktop servers.

1. Make sure that the Remote Desktop server registry has been successfully backed up.
2. Start Registry Editor.
3. Locate and then click the following registry subkey:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM
   
4. On the Registry menu, click Export Registry File.
5. Type exported- Certificate in the File name box, and then click Save.
   
   NOTE: If you have to restore this registry subkey in the future, double-click the Exported-parameters.reg file that you saved in this step.
   
6. Right-click each of the following values, click Delete, and then click Yes to confirm the deletion:
   
   Certificate
   X509 Certificate
   X509 Certificate ID
   X509 Certificate2
   
7. Quit Registry Editor, and then restart the server.
8. Reactivate the Remote Desktop Services Licensing server by using the Telephone connection method in the Licensing Wizard. 

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:

RD Gateway:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;967933 Error message when a remote user tries to connect to a resource on a Windows Server 2008-based computer through TS Gateway by using the FQDN of the resource: "Remote Desktop Disconnected"

http://technet.microsoft.com/en-us/library/ee791928(WS.10).aspx  Group Policy Settings for Remote Desktop Services in Windows Server 2008 R2

http://support.microsoft.com/kb/224395/EN-US/  Remote Desktop Services Client Error Message: You Do Not Have Access to Logon to This Session

http://technet.microsoft.com/en-us/library/cc780927(WS.10).aspx Troubleshooting General Remote Desktop Error Messages

http://support.microsoft.com/kb/329896   Because of a security error, the client could not connect to the Remote Desktop server

http://support.microsoft.com/kb/278433 Accessing Remote Desktop Services Using New User Rights Options

http://support.microsoft.com/kb/258021 Event ID 52 When You Start Remote Desktop Services


If this article does not help you resolve the problem or if you experience symptoms that differ from those that are described in this article, search the Microsoft Knowledge Base for more information. To search the Microsoft Knowledge Base, visit the following Microsoft Web site:

http://support.microsoft.com/ 

Then, type the text of the error message that you receive, or type a description of the problem in the Search Support (KB) box.