Verify that IMAP4 is Available from MS Exchange

This procedure tests whether your MS Exchange is listening on IMAPS port 993.

Reference: Microsoft Technet

• Verify that IMAP4 is available from Exchange
  • From a computer that has network access to MS Exchange, execute the following command, where <Microsoft Exchange DNS or IP> is the DNS or IP address of your MS Exchange

    Test-NetConnection <Microsoft Exchange DNS or IP> -Port 993

The example shows a successful TCP connection test to port 993.

Troubleshooting:

• If the TCP connection test to port 993 fails, verify that your network configurations are not blocking TCP traffic to port 993 between your computer and Exchange.
• If TCP traffic to port 993 is open but the TCP test fails, this means that IMAP4 is not configured and/or listening on port 993.  Follow the instructions in the section Enable IMAP4 in Exchange 2013.