Issue during sign in with Google: The identity received from the authorization provider is already used to sign in by another webtrees user

[Jefferson49]

Observed with webtrees 2.1.25, and version 1.1.9

Issue described in a post in the webtrees forum:

Using the OAuth 2.0 client with Google as provider, I sometimes get the following error message in the DEBUG log: 

OAuth2 Client: The identity received from the authorization provider is already used to sign in by another webtrees user.

Sometimes the authentication works, sometimes it does not and I have difficulties to understand why. I have the impression that the problem depends on whether the user is already logged into their Google account or not. All previous messages regarding the OAuth2 module in the log before the error seem to be normal. 

[Ged296123]

Same error with Authelia...

Normal sign-in is working; signing in with Authelia fails with error "The identity received from the authorization provider is already used to sign in by another webtrees user."

Ended up going to "My Pages >> My Account >> Connect with Authelia" (at very bottom of page).
Took a little time but didnt come across this in any of the documentation.

Seems to have solved the issue on my side.

[Jefferson49]

Ended up going to "My Pages >> My Account >> Connect with Authelia" (at very bottom of page).
Took a little time but didnt come across this in any of the documentation.
Seems to have solved the issue on my side.

Generally, this behavior is part of the module functionality and described in the following: Readme chapter. As a user you can decide about two different ways to connect:

1. Register a new webtrees user based on the identity provided by an authorization provider
2. Connect an existing webtrees user with an authorization provider

If using 1.), OAuth2 client needs to validate the provided email address, because webtrees does not allow 2 users sharing the same email address. If the email validation shows that the email is already used, a message "The identity received from the authorization provider is already used to sign in by another webtrees user" is shown. In this case, it is still possible to use option 2.), i.e. connecting an existing user. I guess that's how you proceeded and it solved the situation for you.

I sometimes get the following error message in the DEBUG log

Seemingly, this is a different issue and happens after the first conncection has already been successfully established. For me, it sounds like there is no error shown in the user frontend. However, something does not work and the described error is logged.