Looking for logging into the Facebook Multiple Domains 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 Multiple Domains site. After that you can login as usual with your login credentials.
https://stackoverflow.com/questions/12296180/facebook-login-with-multiple-domains
https://www.sitepoint.com/community/t/single-facebook-app-with-multiple-domains/99834
https://github.com/hybridauth/hybridauth/issues/795
https://www.drupal.org/project/fb/issues/763926
https://www.drupal.org/project/fboauth/issues/1483124
https://www.facebook.com/help/community/question/?id=592341870905271
https://support.ladesk.com/172666-How-to-setup-Facebook-application
https://wp-native-articles.com/blog/news/how-to-fix-facebook-apps-error-cant-load-url-domain-url-isnt-included-apps-domains/
https://marguspala.com/facebook-login-on-multiple-subdomains-with-one-app-id/
https://www.quora.com/Why-doesnt-Facebook-accept-an-IP-address-as-a-valid-base-domain-for-Facebook-Connect
https://blog.cpanel.com/managing-multiple-domains-from-a-single-cpanel-account/
https://registry.pro/newsroom/blog/everything-you-need-know-about-using-multiple-domains-your-site
https://www.sourcecoast.com/forums/jfbconnect/jfbconnect-joomla-15-support/3514-multiple-fb-apps-on-one-domain