IMAP problem after the coexistence of Exchange2010 and 2013

Some time ago, we did a project to migrate exchange2010 to exchange2013. In order to achieve the effect of smooth migration, we first coexist with 2013, and then migrate mail. However, I encountered a problem in the process of migration, which I would like to share with you. I hope it will be helpful to friends who encounter similar problems.

Environment description: exchagne 2010 sp3 (2 CAS\ HUB, 2 MBX), Exchange 2013 (2 CAS, 2 MBX), coexistence deployment

Description of the problem: after the coexistence of exchange2010 and 2013, all exchange2010 users configured with IMAP repeatedly play verification, as shown below:

The mailbox user IMAP configuration of exchange 2013 is normal.

Process:

Check the IMAP log and find the following error:

Because exchange2010 and 2013 coexist, users of exchange2010 will be proxied to exchange2010 through exchange 2013 when they access IMAP, but when it comes to exchange 2013, NTLM authentication is not supported for IMAP in exchange 2013, as shown in the following figure:

Therefore, there will be the problem of authentication failure in the process of login.

To solve this problem, you need to execute the following command on exchange 2013:

Set-IMAPSettings-EnableGSSAPIAndNTLMAuth:$FALSE

Restart the IMAP service after the command has been executed

Please refer to: https://support.microsoft.com/en-us/help/3006849/gssapi-based-kerberos-authentication-protocol-is-not-offered-to-imap-c