Happened about 2 weeks ago on my Android phone. No problems on my IPAD...
There's no way I'm going to "re authenticate". When I get the chance, I'm going to wipe the phone and go from there.
I don't trust the security in Android.
I think it happened after an OS update pushed from my ISP, but I'm not typing in any passwords to be safe. I bet this all will get tracked back to the ISPs.
I only use the Android as a phone and as a backup way to get emails, so no important data, no rush.