We recently ran into a huge issue stopping the company from being able to function for the past hour, and I wanted to see if anyone could shed some light on this.
A couple weeks back, I started getting a couple reports of Outlook prompting for the credentials. It was only a select few users on the domain that would run into this issue. Everyone else was fine. As the past couple of weeks went by, it seemed like more people started getting the pop up. They could enter their credentials, and it would work, but eventually would pop up again a day or so later.
Then, today, the entire Exchange server went down, so it seemed. Only, all iPhones could still receive e-mail, and Webmail worked just fine. The Outlook clients on every computer stopped working, and would either be in the "Disconnected" or "Trying to connect" state. Sometimes it would prompt for credentials, but the credentials wouldn't work at all this time.
So, we thought, domain controller issues? Were our two domain controllers fighting against each other and causing issues with Exchange?
We shutdown our second domain controller in second building. Then rebooted the primary domain controller in the first building. Waited 10 minutes or so, and turned the second domain controller back on.
Then, I rebooted Exchange and the Edge Server. Still... same problem.
From the event logs, one of our other system admins noticed that the domain controller was, on occasion, allowing authentication requests to go through, and other times. He then disabled the firewall on the domain controller, and the Exchange Server started
working normally.
There have been no changes to the firewall prior to this, it has always been on, until these problems started and forced us to turn off the firewall.
So have you heard of this issue? Or know why the built-in windows firewall "domain profile" would just suddenly take the Exchange Server from prompting for credentials on a couple users, to completely stopping the domain controller from working?