Looking for logging into the Joomla Mainframe 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 Joomla Mainframe site. After that you can login as usual with your login credentials.
https://docs.joomla.org/API15:JApplication/login
https://joomla.stackexchange.com/questions/22945/how-can-i-use-a-username-and-password-to-login-with-php
https://stackoverflow.com/questions/2075335/how-to-log-into-joomla-through-an-external-script
https://www.aftercube.com/tweaks-and-tricks/2-using-joomla-session-and-user-login-in-an-external-script
https://groups.google.com/d/topic/joomla-dev-general/rVUkg0wzLOY
https://books.google.com.ph/books?id=Z4cY24m-xbgC&pg=PA55&lpg=PA55&dq=joomla+mainframe+login
https://github.com/techjoomla/Joomla-REST-API/blob/master/joomla_1.6/server/index.php
https://www.itoctopus.com/fixing-the-login-twice-and-the-logout-twice-problem-on-your-joomla-frontend
https://books.google.com.ph/books?id=a_QzDQAAQBAJ&pg=PA497&lpg=PA497&dq=joomla+mainframe+login
https://www.ostraining.com/joomla-support/9449-can-t-log-in-to-admin/
https://www.carnaghan.com/knowledge-base/how-to-redirect-using-the-joomla-1-5-and-2-5-api/
http://qaru.site/questions/640580/how-to-log-into-joomla-through-an-external-script
https://econcepts.co.uk/snippets/joomla-how-give-a-registered-user-a-specific-page-login