I am getting the same on 3.4
1) existing customers are unable to login to their accounts. Can they link an email id to the a/c created by Fb login? Any way to sidestep Fb login and login?
2) Facebook replied "Thanks for the additional information - unfortunately we can't support issues that you encounter using 3rd Party Applications which are built on top of the Facebook SDKs. I have gone through the sign up flow on both of your sites. The Facebook Login dialog loads correctly, the permissions are requested and granted. The error occurs after Facebook has successfully granted the user permission to your App and redirects to your website with the authentication details. At this stage it is your redirect URI that is failing to handle the response from Facebook correctly. To get more information on the error and how to resolve it you would be best placed to contact moodle directly. "
Valid OAuth redirect URIs:
https://www.website.in/admin/oauth2callback.php
https://www.website.in/_oauth2/login.php
3) DEBUG
This page did not call $PAGE->set_url(...). Using
Error code: Could not upgrade oauth token $a contents: Stack trace: line 559 of /lib/oauthlib.php: moodle_exception thrown line 473 of /lib/oauthlib.php: call to oauth2_client->upgrade_token() line 44 of /auth/oauth2/login.php: call to oauth2_client->is_logged_in()
4) Unable to connect System Account.What is a system account? I already have a system administrator account. How can I create one?
'Create a new user' is not working.