Why do my Google contacts have a sync failure?

[AC Question]

Google contacts sync failure

My Contacts stopped syncing after I switched to two step authentication. All other google services still sync fine.

I have searched for a solution extensively on the boards and tried everything they recommend short of a hard reset. This includes removing 2 step authentication and then the google account, before re-adding the entire google account.

Have also tried deleting the contacts cache and contacts data.

Nothing works

I'm loathe to do a hard reset for obvious reasons. Any other suggestions that I might try?

I'm not rooted, using Lollipop 5,0.

Any suggestions very gratefully received.

Thanks