Looking for logging into the Phpbb8 Backend White Page 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 Phpbb8 Backend White Page site. After that you can login as usual with your login credentials.
https://forum.joomla.org/viewtopic.php?t=931400
https://www.phpbb.com/community/viewtopic.php?f=46&t=1452475
https://wordpress.org/support/topic/i-cannot-access-my-wp-admin-page-it-shows-up-blank/
https://wordpress.org/support/topic/website-shows-blank-page-unable-to-login-to-wp-admin-as-this-is-also-blank-page/
https://expressionengine.com/forums/archive/topic/235452/cant-login-to-admin-just-presented-with-a-blank-white-page
https://rockettheme.com/forum/general-discussion/178344-solved-website-goes-to-blank-white-screen-rokgallery
https://rockettheme.com/docs/phpbb/start/rocketlauncher.md
http://www.inmotionhosting.com/support/website/website-troubleshooting/my-wordpress-site-is-displaying-a-blank-page
https://forum.opencart.com/viewtopic.php?t=41010
https://www.hostinger.com/tutorials/fix-wordpress-login-redirect-loop
https://www.mediawiki.org/wiki/Extension_talk:Phpbb_Single_Sign-On
http://www.inmotionhosting.com/support/edu/wordpress/wordpress-introduction/logging-into-wordpress-dashboard
https://www.dokuwiki.org/tips:integrate_with_phpbb