Outlook Login Popup

Recently an employee brought this annoying little issue to my attention. It seems when he responds/opens certain emails he gets a login screen that says connect to....blah blah. No matter what you enter in it keeps coming back up.

However, if you just cancel it or click ok enough times it goes away and you can continue to work. Why would this happen and how come it doesn't seem to actually affect any of this persons work.

Some things I took note of was that he changed his email address(which was done through active directory), but still logs in as his old login. Would that have anything to do with it is outlook just confused as to who he is or is this some stupid bug in Outlook or Exchange?

I also noted that when I opened up his email I to was prompted for a login/password, but by simply canceling it, it goes away and I can continue to work. Any ideas?

Is the option to "remember" password checked in the account properties, probably not if it's prompting you for a password...

Tools/Accounts/mail/properies/servers... under the Incoming Mail Server... information should be an option to "remember password"..;)

The only time I've seen outlook prompt for UID and PWD when connecting to exchange was when the user's password was either expired and has to be changed, or the user's account was locked out. I had one case where the password change didn't sync and they had to log off and back on after changing their password.

Have you looked at the exchange server's security log?

I took a look at the security log and nothing seems out of order.

I also checked on his account and saw the password never expires is not checked, but that doesn't really seem to be the issue.

This only happens when opening a emails from a specific alias so I am not sure why it would only target one but not all emails he receives. When he sent me the email he was having the issue with it also asked me for a login/pw, but that has never happened to me before.

Could it be something with his account specifically or with that alias. It is a very strange occurrence to say the least.

He logs off and on each night and morning. He changed his email about 6 months ago, but still logs into his computer with his old email/login name. Could that be an issue. Or perhaps I am missing some key part of information here. Thanks for the ideas so far.