There may have been some issues with Google today.
I got these errors earlier that describe an authentication backend failure, but then an hour later they disappeared:
One online newspaper here in the UK reported: “Gmail and other Google services stopped working after a major outage for the technology giant on Monday. Google said the issue affected “a majority” of the 1.5 billion users of its email platform. Gmail users were greeted with a “Temporary Error” message, stating: “We’re sorry, but your account is temporarily unavailable.” “We’re aware of a problem with Gmail affecting a majority of users,” the message added, with the word “Gmail” later replaced with “services”.
Limited functionality returned after around 30 minutes, though users were still unable to access their contacts. It took a further 15 minutes for the service to be fully restored.”
Maybe it is related? ;-(