Looking for logging into the Unifi Failed 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 Unifi Failed site. After that you can login as usual with your login credentials.
https://community.ubnt.com/t5/UniFi-Wireless/Cannot-login-to-UniFi-controller-Invalid-username-and-or/td-p/2098405
https://community.spiceworks.com/topic/1851366-unifi-controller-login-problem
https://forum.fhem.de/index.php?topic=89328.0
https://community.unifi.com.my/t5/playtv/Can-t-Login/ta-p/8996
https://github.com/home-assistant/home-assistant/issues/20027
https://community.home-assistant.io/t/ubiquiti-unifi-component-doesnt-work/24754
https://www.reddit.com/r/Ubiquiti/comments/7e1f7u/cloudkey_configure_login_works_management_login/
https://serverfault.com/questions/835410/why-does-my-unifi-hardware-tell-me-adoption-failed
https://www.troyhunt.com/ubiquiti-all-the-things-how-i-finally-fixed-my-dodgy-wifi/
https://ask.linuxmuster.net/t/update-problem-bei-unifi/1154
https://www.tm.com.my/OnlineHelp/CustomerSupport/Self-Help/pages/Home.aspx
https://www.miro.co.za/unifi-social-media-guest-authentication/
https://gathering.tweakers.net/forum/list_messages/1801151