Can't Login into Adwords Accounts

I get the following error (see attached) when trying to re-add my adwords account.

I already had Adwords connected, but for some reason I wasn't able to select an account from the drop-down list (which has never been a problem before). When I tried refreshing, it did nothing so I just logged out of all accounts and tried to log back in. 

When I did so, I selected the google account and then I got the error. I've restarted my computer twice, still nothing.

I need this resolved immediately. Please advise.