Looking for logging into the Facebook Email Undefined site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Facebook Email Undefined site. After that you can login as usual with your login credentials.
https://stackoverflow.com/questions/18166089/unable-to-access-users-email-getting-undefined
https://github.com/jaredhanson/passport-facebook/issues/214
https://github.com/jaredhanson/passport-facebook/issues/134
https://github.com/Wizcorp/phonegap-facebook-plugin/issues/1335
https://developers.facebook.com/docs/facebook-login/handling-declined-permissions/
https://developers.facebook.com/docs/reference/javascript/FB.login/
https://code.i-harness.com/en/q/7754c5
https://www.back4app.com/docs/javascript/javascript-facebook-login
https://www.drupal.org/project/fbconnect/issues/1324150
https://www.drupal.org/project/fboauth/issues/2496441
https://howtofirebase.com/firebase-authentication-for-web-d58aad62cf6d
https://forums.expo.io/t/i-cannot-get-a-users-email-when-i-use-facebook-login/5172
https://help.powr.io/hc/en-us/articles/115002378007-Facebook-Social-Feed-returns-undefined-and-does-not-load