A mobile device can't connect to Exchange Online by using Exchange ActiveSync

A user's mobile device can't connect to Microsoft Exchange Online in Microsoft Office 365 through Microsoft Exchange ActiveSync. However, the mobile device previously could connect.

This issue can occur for many reasons. These include, but aren't limited to, the following:

• The device can't connect to the Internet service provider (ISP) or to the Internet.
• The device isn't set up correctly.
• The Exchange Online mailbox server that supports the connection isn't available because of maintenance or an outage issue.

To fix this issue, follow these steps.

Step 1: Confirm that ActiveSync is enabled for the user

In Office 365

1. Sign in to the Office 365 portal (https://portal.microsoftonline.com
   (https://portal.microsoftonline.com)
   ) as an admin.
2. Click Admin, and then click Exchange to open the Exchange Admin Center.
3. In the left navigation pane, click Recipients, and then click Mailboxes.
4. In the list of mailboxes, double-click the user, and then click Mailbox Features.
5. Under Mobile Devices, take the following actions:
   1. If you see Disable Exchange ActiveSync, this means that ActiveSync is enabled for the user. Go to "Step 2: Confirm that the mobile device isn't blocked by an ActiveSync quarantine rule."
   2. If you see Enable Exchange ActiveSync, this means that ActiveSync isn't enabled for the user. Click Enable Exchange ActiveSync, click Yes when you're prompted, and then click Save.
6. After you re-enable ActiveSync, try to set up the device again.

In Office 365 pre-upgrade

1. Sign in to the Office 365 pre-upgrade portal (https://portal.microsoftonline.com
   (https://portal.microsoftonline.com)
   ) as an admin.
2. Click Admin, and then, under Exchange, click Manage to open Exchange Control Panel.
3. In the left navigation pane, click Users & Groups, and then double-click the user mailbox.
4. Expand Phone & Voice Features, and then make sure that Exchange ActiveSync is set to Enabled. If it's not enabled, enable it.
5. Click Exchange ActiveSync, click Edit, and then note the ActiveSync device policy that's assigned to the user.
6. After you re-enable ActiveSync, try to set up the device again.

Step 2: Confirm that the mobile device isn't blocked by an ActiveSync quarantine rule

In Office 365

1. In the Exchange Admin Center, click Mobile, and then click Mobile Access.
2. Confirm that the user's mobile device isn't in the list of quarantined devices.

In Office 365 pre-upgrade

1. In the left navigation pane of Exchange Control Panel, click Phone & Voice, and then click ActiveSync Device Policy.
2. Click the ActiveSync device policy that you determined in step 1, and then click Details. Make sure that the policy allows the user's device. If the ActiveSync device policy doesn't allow the user's device, edit the policy to allow the device. Or, assign an ActiveSync device policy that does allow the device to the user.
3. Click ActiveSync Access, and then take the following actions:
   1. Under Exchange ActiveSync Access Settings, make sure that the device is allowed.
   2. Make sure that the device isn't in the Quarantined Devices list.

Step 3: Confirm that ActiveSync can be set up by using Autodiscover

The Autodiscover service makes it easier to set up Outlook and mobile phones. The Autodiscover service uses a user's email address and password to automatically set up a user's profile.

To troubleshoot this issue further, run the Exchange ActiveSync Autodiscover test in Microsoft Remote Connectivity Analyzer or the Exchange Online test in the Microsoft Online Services Diagnostics and Logging (MOSDAL) Support Toolkit. If the user is using a local wireless network to connect to Exchange Online, the user should run both tests to make sure that the local network allows for connections to the ActiveSync endpoints.

Test Exchange Online ActiveSync access externally by using Remote Connectivity Analyzer

Note Admins may want to guide users through running Remove Connectivity Analyzer if this is necessary. The Exchange ActiveSync Autodiscover test requires the user to enter his or her credentials.

1. In a web browser, browse to the Microsoft Remote Connectivity Analyzer tool at the following website:
   https://www.testexchangeconnectivity.com

   (https://www.testexchangeconnectivity.com)
2. Click the Office 365 tab.
3. Under Microsoft Exchange ActiveSync Connectivity Tests, click Exchange ActiveSync Autodiscover, and then click Next.
   
   
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4. Enter your Office 365 sign-in credentials.
   
   
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5. Click Perform Test, and then wait while the details pane is displayed.
   
   
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6. Review the test results.
   
   
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7. Take one of the following actions:
   • If the test passes, follow the steps in the Mobile Phone Setup Wizard
     (http://help.outlook.com/en-us/140/dd936215.aspx)
     to set up the mobile device.
     
     If you're trying to access ActiveSync by using a local wireless network, you should also test access internally by using the MOSDAL Support Toolkit. For more information about how to do this, see the "Test Exchange Online ActiveSync access internally by using the MOSDAL Support Toolkit" section.
   • If the test fails, confirm that the Autodiscover service is set up correctly. To set up Autodiscover, follow the steps on the following Microsoft website to set your CNAME record:
     Use a CNAME Record to Enable Outlook to Connect

     (http://help.outlook.com/en-us/140/cc950655.aspx)

Test Exchange Online ActiveSync access internally by using the MOSDAL Support Toolkit

1. Download and install the MOSDAL Support Toolkit from the following Microsoft website:
   http://www.microsoft.com/download/en/details.aspx?id=626

   (http://www.microsoft.com/download/en/details.aspx?id=626)
2. Run the MOSDAL Support Toolkit, click Email and Calendar with Exchange Online on the Office 365 tab, and then click Next.
3. Enter the credentials of the affected user, and then click Next.
4. On the "Reproduce your problem" page, click Next.
5. When the test is finished, click Exit and Show Files.
   
   Note You can manually access the results files by going to the \Documents\MOSDAL folder.
6. Locate the \Admin_Applications\Exchange\Exchange_RCA folder, and then open the Results.html file.
7. Review the information under the ExRCA is testing Exchange ActiveSync section of the Results.html file.
   • If the test passes, the local network is enabling access to the Exchange ActiveSync Service endpoints by using Autodiscover. See the Mobile Phone Setup Wizard
     (http://help.outlook.com/en-us/140/dd936215.aspx)
     for instructions for setting up the mobile device.
   • If the test fails, use the results to determine why your local network may be blocking access to Exchange ActiveSync. Try to connect by using the data connection that your service provider provided.

Step 4: Set up the mobile device without using Autodiscover (if you don't want to use Autodiscover)

We recommend that you use Autodiscover when you try to set up mobile devices. However, if you want to set up a mobile device without using Autodiscover, use the procedure that is described on one of the following Microsoft websites:

• Set up email on Apple iPhone, iPad, and iPod Touch
  (http://office.microsoft.com/redir/HA102818554.aspx)
• Set up email on a BlackBerry
  (http://office.microsoft.com/redir/HA102823192.aspx)
• Set up email on Windows Phone
  (http://office.microsoft.com/redir/HA102823194.aspx)
• Set up email on an Android phone or tablet
  (http://office.microsoft.com/redir/HA102823196.aspx)

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

Still need help? Go to the Office 365 Community website.