Looking for logging into the _session 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 _session site. After that you can login as usual with your login credentials.
https://stackoverflow.com/questions/42590634/undefined-variable-session-php-login-script
https://www.formget.com/login-form-in-php/
http://php.net/manual/en/reserved.variables.session.php
https://www.w3schools.com/php/php_sessions.asp
https://www.johnmorrisonline.com/build-php-login-form-using-sessions/
https://expressionengine.com/forums/archive/topic/121776/undefined-variable-_session
https://books.google.com.pk/books?id=DQRBMWN_VJ0C&pg=PA430&lpg=PA430&dq=_session+login
https://www.drupal.org/project/simple_pass_reset/issues/2111293
https://en.wikipedia.org/wiki/Session_poisoning
https://www.sitepoint.com/forums/showthread.php?592619-Session-variables-not-carrying-over-to-my-login-page-but-session-ID-is
http://www.2person.in/how-to-make-login-form-in-php-with-session/
http://www.java2s.com/Code/Php/Cookie-Session/checkforavalidlogininsessions.htm
https://www.mediawiki.org/wiki/Topic:Tvx6bgsxmwktdye9