Hello Experts Exchange
I have an issue with pop3 logins in an Exchange 2010 DAG environment. WE have two servers holding the Mailbox Server role and one holding the CAS and Hub Transport roles. The passive Mailbox server is in another site, there is no firewall in between.
Everything works fine when mailboxes are on the active mailbox database but were failing recently. Upon logging into the Exchange Management Console we noticed that the Exchange server had failed over to the copy mailbox server. Once we moved the active copy back the the original server pop3 logins worked again.
To test I have created a single instance database and mailbox on the passive copy server and pop3 logins fail with the error "-ERR Login Failure. Unknown Username or password"
Help much appreciated.