Error message when you try to connect to a Windows server-based computer that is running Terminal Services: "Terminal Server has ended the connection"


When you try to connect to a Microsoft Windows server-based computer that is running Terminal Services, you may receive the following error message:

Terminal Server has ended the connection.
In the Terminal Services application event log you may find this event:

Event ID 1004
Source: TermService
Description: Unable to acquire a license for user XXXXX, domain XXXXX


This message may be caused by a difficulty in communicating over the network, and not by an actual licensing issue. Terminal Services and the client may be have difficulties communicating over the local area network (LAN), the wide area network (WAN), or the virtual private network (VPN) that they are using to establish the session.


To determine the cause of the problem, follow these steps:

  1. You can verify connectivity by pinging from the client to Terminal Services, and from Terminal Services to the client by IP address. If you are connecting to Terminal Services by name, verify that you can ping by name also. If you can ping successfully, go to step 2. If pinging fails, verify the IP configuration information of Terminal Services, and the client to make sure that it is correct, and that Terminal Services, or the client are able to find the path to each other. To do this, you may have to verify routing information on Terminal Services, and/or correct default gateways on both the client, and Terminal Services.
  2. You can try pinging by using a fixed packet size of 1472 bytes with the Don't Fragment bit set. This represents the largest Internet Control Message Protocol (ICMP) packet that can be sent by using the Ethernet media. This varies depending on the media that is involved.

    ping -l 1472 -f IP address
    If this does not work, try using smaller, and smaller numbers in the ping command until you receive a response. The size that you used to receive a response is the maximum size packet that is allowed over the network, which the client and/or Terminal Services are traversing.
  3. If the packet size that you were able to ping with was smaller than the maximum packet size for the network media, you may have to configure Terminal Services and/or the client by referencing the articles that are listed in the "More Information" section. One of those solutions should resolve the problem that you are experiencing.
Note You must make sure that there are licenses installed on the Terminal Services License Server. If there are no available licenses, the event 1004 will also occur.

More Information

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

159211 Diagnoses and treatment of black hole routers

314496 The default MTU sizes for different network topologies

120642 TCP/IP and NBT configuration parameters for Windows 2000 or Windows NT

183229 RAS uses fixed TCP/IP MTU size

158474 Windows TCP/IP registry entries

For additional information about Terminal Services licensing issues, click the following article numbers to view the articles in the Microsoft Knowledge Base:

237811 How to activate a Terminal Services License Server and install CALs over the Internet

823313 Windows Server 2003 Terminal Server licensing issues and requirements for deployment

239107 Establishing preferred Windows 2000 Terminal Services License Services

237801 Windows 2000 Terminal Services Requires Licensing Service
244749 Licenses required when using Terminal Services client software


Article ID: 274805 - Last Review: Jun 25, 2009 - Revision: 1