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Some users cannot log in via POP3

Last Modified: 2012-02-18
Using Exchange 2010.... we have a few users who for the life of me I cannot get to login to their POP3 account successfully. The Error is ERR Logon failure: unknow username or bad password.

They can log in fine via OWA, and they log in to the same server, in the same manner that users who work do... it's very odd and quite frustrating.

Anyone ever see this behavior before?
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Top Expert 2010

a) Check if you are port forwarding 110 to internal LAN IP of Exchange server on firewall.
b) Check if POP3 services is configured in Exchange and the service is running.


Cheers for the response...all of the above has been checked and working as intended. And as previously stated...POP3 does in fact work for some users. For some reason, it just doesn't work with a select few. It's very selective....with no rhyme or reason....
Top Expert 2010

What email client are you using ?

From the users computer run this

start > run > cmd
telnet mail.domain.com 110

If you get the Exchange banner, then the problem is somewhere else.
If you dont get the exchange banner with mail.domain.com, then there is an issue in the network layer. Check if the ISP allows 110 ..
Rajkumar DuraisamyRajkumar Duraisamy (Rajkumar-MCITP)
Top Expert 2012

Error message shows, its a logon failure due to bad credential.

While configuring pop3, on the User Name, instead of user alias name, type the email address and configure the pop3 profile

Inform if the error message appears again
Elmar KoschkaSenior System Engineer

POP is enabled for User in the Exchange User Config ?!


POP is enabled for all users on Exchange.

I have tried logging in as both DOMAIN\user and the full UPN format. No dice.

At the moment we are using Outlook to test these POP accounts and can telnet successfully to the mail server on both ports 110 and 995 (we're only using 995).

Again, I do not want to overstate the obvious or continue to sound redundant.... but this does work for some users and just doesn't work for others. I mean, this is pretty simple stuff we're talking about here.... so I'm kind of hoping that others have come across this anomaly as I reckon the resolution is quite rudimentary.
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