Troubleshooting EAS that stopped processing on a Exchange 2010 Server

Scenario: We had an Exchange 2010 server that stopped processing requests for Exchange Active Sync. Users were getting the error “Unable to verify the account information” on their mobile devices or other connection related messages. This problem was not enterprise wide and only a problem for whichever mailboxes were hitting this one Exchange 2010 Client Access server.

Solution: We had to find the server that was not processing the Exchange Active Sync requests. Once rebooted, the server started processing the requests again. Below are the key troubleshooting steps we took to validate the problem on the single server.

Troubleshooting Steps:

1. Test the problem user’s account with Microsoft Remote Connection Analyzer – Exchange ActiveSync test (https://testconnectivity.microsoft.com/). Where the test was failing, there was a common X-CalculatedBETarget Exchange 2010 server amongst all of the accounts.

2. In a web browser, going to the website: https://<servername>/Microsoft-Server-ActiveSync and comparing the behavior of the failed server to a good server. On the failed server we were getting the error message: 500 – Internal Server Error. There is a problem with the resource you are looking for, and it cannot be displayed. On the good server we were getting: The page cannot be displayed because the HTTP version is not supported. This let us know that this server was having a problem with the IIS website.

3. Taking it a step further, we browsed to the ActiveSync site from the Servers IIS manager. Here we got a similar, but more detailed error: HTTP Error 500.19 – Internal Server Error. The requested page cannot be accessed because the related configuration data for the page is invalid. Comparing these contents to a working server’s content, this helped support that there was a server problem.

4. Reviewing the IIS logs for this Ex2010 server also revealed that every ActiveSync request had a Http code of 500 (the 4th column from the end of each log entry).

5. Restarted the Server -- ActiveSync worked on that server when it came back up.