I just recently factory restored my windows drive and I noticed that during the set up phase I was not prompted to set my time zone. The same thing happened when I upgraded to 8.1. Since then I kept getting a message to verify my account info. Go to PC Settings, access more settings online in User Accounts and edit your Personal Profile. The time zone info in my was completely wrong. I'm not sure that this is the root of the problem but I just wanted to pass this info on.
That was not the problem I had. My replacement tablet works fine. Of course, it took over 6 months for Dell to agree to do that. I am glad you solved your problem.