- You just updated a couple of gems including the omniauth google oauth one ?
- Your oauth callback is now failing ?
Well, don't worry it's not too bad.
Google decided to deprecate some of its OAuth endpoints and OmniAuth updated its code before the September deadline.
Yet, as there is little documentation about this changes a lot of us went through a difficult time.
The solution is simple : activate the Google+ API for your account.
It was documented in an issue : https://github.com/zquestz/omniauth-google-oauth2/issues/111#issuecomment-44718385 , and @olivierlacan introduced a CHANGELOG in a PR to document such changes : https://github.com/zquestz/omniauth-google-oauth2/issues/132 .