I have seen this popping up lately when using my older Android devices
The M8 Android Box for example.
I sued to think it was just a Google Account sync issue or sign in issue, but it seems to be more than that.
What used to work fine on my M8 Android Box, now gives me grief, EG: YouTube app i get the "Not Supported" message.
I've tried some methods mentioned here:
All apart from the last Method (Factory Reset), as i'm not prepared to load everything back on just yet.
Anyone else been stuck with this problem?
Found a way around it?