I've been trying to upgrade to Plus all day but, after entering my billing credit card info, I get a message saying "Something has gone wrong. Please try again later." I saw other references that recommended trying a different browser so I have tried Edge, Chrome, and Firefox with the same results.
No, I think I'm good now. My credit card had a fraud alert from all the online Christmas purchases and it had declined the transaction. It would have been nice if the error message had said "Your card was declined." instead of "Something has gone wrong. Please try again later." That way I could have checked out my credit card earlier.