For some reason I got logged out earlier today and now it won’t log me in at all, it says it can’t verify the account information. My Authenticator was also logged out and when I try to login to it I get
“Your sign-in was successful but you don’t have permission to access this resource.”
Are you trying to log into classic or retail? Is it possible your account ran out of game time?
Not sure if related, but I can’t see any of my retail characters on the forums when I go to change my character. 4 months of game time left. 
Should add, this happened in the last 20 minutes.
This just happened to me, for some reason the only character I can see for the forums is this throwaway classic alt I made for some mount promotion.
I can’t even log into Battlenet to check if game time ran out. But as you can see I can post on the forums.
Just for clarification, game time isn’t needed to post on the Support forums. You do need a sub to post in any other but this one is special since it’s more support oriented.
There maybe an issue going with the log in servers or a maintenance.
https://us.support.blizzard.com/en/help/contact/2185/ticket
You can follow the link above to get to a Can’t Log In ticket path. You can do this without actually logging into Battle.net.
I could post on all forums.
So its working now and the reason is kinda horrible.
So I’ve been using my college email as my primary for 22 years.
6 years ago the college switched over to Office 365 and transferred all emails over to MS servers.
2 Months ago the college decided to no longer pay for 365, thus we shouldn’t use the college emails as a primary email anymore. They notified staff, and current students but not Alumni.
MS blocked my access to my college email when the license expired.
It appears that they blocked everything attached to that email as well.
Thus my Battle.net was locked out as well. So I managed to get them to give me 30 days access and I have to change everything from that email address.
So FYI, don’t attach Battle.net to any MS account that they authenticate for, otherwise you can get locked out as well.
Oof, that sounds horrid. I hope it isn’t too much an ordeal to migrate your email.
I moved to a paid provider and maintain my own domain name just to have better control over my email.
Once I got access back I could then change the primary email, switched it to my Outlook email so it shouldn’t happen again…but its MS lol
Man I thought I had been hacked. Ugh. no Hearthstone for me tonight.