Hi,

Please make sure the related IMAP and POP services are started and running in Exchange server side. And try to setup the problematic user's account in the machine which is working normally with IMAP and POP3 to check whether the issue persists.

Regards,

We have exchange 2013 setup with 3 mailbox and 3 CAS servers.

Everything was fine until yesterday and suddenly POP3 and IMAP users login failed and  they are no able to login using outlook.

Exchange MAPI configuration and accessing email over WEB is fine. Those who are using POP and IMAP failed.

We tried to create new profile for the POP and that also failed with message

"Log onto incoming mail server (POP3): Your e-mail server rejected your login. Verify your user name and password for this account in Account Settings.  The server responded: -ERR Logon failure: unknown user name or bad password."

If anybody have similar experience or any solution kindly help please 

HI

Anyone have any comments.

Still we are unable to fix the issue.

It is happening for some users.

Some users it is working?