Hi,

We setup Coexistence of Exchange 2007 and Exchange 2013. There are 2 Exchange 2007 Servers (1 x Mailbox Role and 1 x CAS & Hub transport role) and 2 Exchange 2013 Servers (1 x Mailbox Role and 1 x CAS Role).

After we placed the Exchange 2013 CAS as the Front End Server, some users who are using POP3 are unable to receive email because their previous settings have the Secure Password Authentication (SPA) Enabled. It seems that Exchange 2013 is denying the SPA. Disabling the SPA allows the users to receive email. 

I did some test and no matter where the mailbox server resides, the Exchange 2013 CAS is rejecting SPA. When manually pointing the pop3 server to the Exchange 2007 CAS, SPA is working. What can we do to let the Exchange 2013 CAS to allow SPA?

Both Exchange 2013 Servers are on CU7.

Regards,

Arthur Villanueva

Hi Arthur,

Please do the following POP settings in Exchange 2013 and check whether the issue persists:

Get-PopSettings | Set-PopSettings -EnableGSSAPIAndNTLMAuth $False -LoginType PlainTextLogin

Restart related Exchange Pop3 service in Exchange 2013 to have a try.

Regards,