Several friends having trouble signing into Communities

I have had a couple of people call me because they can't sign into the Communities forums. I know they have accounts (or should have accounts!) so I have no idea why they are unable to sign in. I am not their administrator, and they are in different offices, so I have no power to do anything, but I can certainly ask here and relay answers.

One of them sent me a picture of the error message he is getting:

Not sure if the other is getting the same or a different error.
Is there anything going on with the community login or IMS?

Thank you.