Looking for logging into the One For Multiple Sites 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 One For Multiple Sites site. After that you can login as usual with your login credentials.
https://stackoverflow.com/questions/44509/single-sign-on-across-multiple-domains
https://laracasts.com/discuss/channels/general-discussion/one-login-for-multiple-sites
https://world.episerver.com/forum/developer-forum/-Episerver-75-CMS/Thread-Container/2015/8/one-login-to-admin-for-multiple-sites/
https://www.quora.com/How-can-I-build-a-single-page-multi-site-login
https://forums.asp.net/t/1814547.aspx?How+to+manage+login+to+multiple+sites+from+single+login
https://drupal.stackexchange.com/questions/233274/one-account-shared-by-multiple-sites
https://www.onelogin.com/product/sso
https://codeutopia.net/blog/2008/09/25/sharing-authentication-over-multiple-sites-single-sign-on/
https://forums.whirlpool.net.au/archive/536551
http://www.shaplus.com/Internet-software/multiple-login-software/QuickLogin/quicklogin-features.htm
https://auth0.com/universal-login
https://www.sitepoint.com/community/t/how-hard-is-it-to-create-a-single-sign-on-for-multiple-websites/207053
https://mailchimp.com/help/manage-multiple-accounts-with-one-login/