Acrobat DC is stuck in a log-in loop
I have an Adobe Creative Cloud account. I cannot open Acrobat DC. When I click to open, it asks me...

When I click "Sign In" I get this window...

(Which is my account name under the black boxes). When I click "Continue", I'm taken back to the first window after a couple of seconds and the whole process repeats.
I'm on version 19.0 running Windows 7 (with all updates applied)
Does anyone have any ideas?
Thanks
