Question

Customer cannot connect to newly provisioned Exchange 2010 mailbox via IMAP. The error message about invalid credentials is shown. What actions can be performed to troubleshoot the issue?

Answer

  1. Use the article https://kb.parallels.com/en/116156 to check that the user is not locked

  2. Check whether it is possible to access this mailbox via OWA and POP3.

  3. Test IMAP connection using powershell cmdlet Test-ImapConnectivity. Do it for all CAS servers in Exchange infrastructure:

    [PS] C:\Windows\system32>Test-ImapConnectivity -ClientAccessServer:pemexcas01 -MailboxCredential(Get-Credential domain.tld\testuser) | fl
    
  4. If you have found CAS server that experiences the authentication issue, check Event Viewer on this server for any errors

  5. Compare IMAP settings of this CAS server with settings on other CAS servers. It can be done using Get-ImapSettings cmdlet:

    [PS] Get-ImapSettings | format-list
    
  6. Restart IMAP4 service according to the article http://technet.microsoft.com/en-us/library/bb124022.aspx

  7. If restart does not help, try to increase IMAP4 service logging according to the article http://technet.microsoft.com/en-us/library/aa997690.aspx and check if there are any detailed errors. Do not forget to decrease/disable logging back after troubleshooting is completed.

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