Looking for logging into the Nextcloud Can't As Admin 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 Nextcloud Can't As Admin site. After that you can login as usual with your login credentials.
https://help.nextcloud.com/t/cant-login-on-nextcloud-14-web-gui/36630
https://help.nextcloud.com/t/solved-cant-login-via-web-ui-anymore/31483
https://help.nextcloud.com/t/logging-problem-nextcloud-13-0-3-redirects-me/32714
https://github.com/nextcloud/server/issues/13090
https://help.nextcloud.com/t/cant-login-to-my-cloud-web-based/10334
https://github.com/nextcloud/user_saml/issues/242
https://github.com/nextcloud/server/issues/2967
https://help.univention.com/t/can-not-login-as-admin-nextcloud/8926
https://github.com/nextcloud/server/issues/10085
https://discourse.mailinabox.email/t/solved-nextcloud-admin-unavailable/3628
https://www.reddit.com/r/NextCloud/comments/81wrir/cant_login_to_nextcloud_but_can_access_the/
https://forums.freenas.org/threads/reset-admin-password-in-nextcloud.63170/
https://forum.yunohost.org/t/no-more-access-in-nextcloud/4170