Sign-in error for name@gmail.com on Android device [SOLVED!]

All of a sudden logging in to my Google Play account was giving an error and I seemed to be locked out!  Bad situation to be in – I couldn’t upgrade any of my apps – and I needed to do an upgrade because WhatsApp had expired – with error “This version of WhatsApp is too old – you need to upgrade”… OK, but I first needed to solve the error “Sign-in error for name@gmail.com”.

I Googled a bit, then a lot more but nothing worked - then I decided to try something out – I changed the language of my account – I noticed that it wasn’t set to anything.  I logged in to my Google account, then clicked “Account” and saw the “Default languages”: 


I changed it from “Select a language…” to English (United States):
 
Then I tried to login on my Android phone and to my absolute amazement I was logged in :)  No error, just logged in.
I could then switch to the WhatsApp upgrade warning message and update to the latest version – problem solved!
This is one of those out of the blue, accidental fixes that somehow worked… I was amazed and I hope this helps someone out there – please let me know by adding a comment.