I have just finished a migration from 2007 to 2013. It's been terrible, just went through a lot of problems. For the most part, most things are working, except, all external users, are being prompted for a username/password prompt. Even though they enter their credentials, it still prompts them.
I made sure and the accounts are NOT locked out.
I even deleted the outlook profile, even deleted the ost file, still nothing.
I even found on a post the following:
1. Start CMD: type the following: control/name Microsoft.credentialmanager
2. Look for anything that looks like Msoutlook:emailaddress…. (remove it from the vault)
3. Restart Outlook (if prompted, enter the user/pass again)
Still doesn't work. On one of the PCs, I even upgraded to outlook 2013, and it still didnt' work. Not sure what else to do?
I already shutdown my exchange 2007, but I don't think that has anything to do with it, because it was causing other routing problems internally, so as soon as I shut it down, it fixed my other problem.
Any ideas? I have about 7 or 8 remote users that are experiencing this issue.