Looking for logging into the Failed For User & 39 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 Failed For User & 39 site. After that you can login as usual with your login credentials.
https://social.msdn.microsoft.com/Forums/sqlserver/en-US/20faacf4-6e5d-4306-ad55-5e1f49d2e580/login-failed-for-user-3939-the-user-is-not-associated-with-a-trusted-sql-server-connection?forum=sqldatabaseengine
https://stackoverflow.com/questions/22415319/system-data-sqlclient-sqlexception-login-failed-for-user
https://forums.asp.net/t/2126831.aspx?Login+Failed+for+user+when+opening+connection+with+SQL+Server
https://dba.stackexchange.com/questions/13005/ms-sql-server-2008r2-login-failed-for-user-from-time-to-time-iis-7-net-4-0
https://security.stackexchange.com/questions/184717/database-logs-have-multiple-logon-login-failed-for-user-from-different-ips
https://www.tntware.com/donorwise/faqs/en/how-do-i-get-past-quot-sql-server-login-failed-for-user-39-39-quot.aspx
https://administrator.de/forum/microsoft-sql-server-2016-login-failed-user-sa-agent-342372.html
https://community.powerbi.com/t5/Report-Server/DirectQuery-Login-failed-for-user-NT-AUTHORITY-ANONYMOUS-LOGON/td-p/310557
http://www.dnnsoftware.com/forums/threadid/478850/scope/posts/login-failed-for-user-39nt-authoritynetwork-service-39
https://www.codeproject.com/Questions/558566/LoginplusfailedplusforplususerplusIISplusAPPPOOL-5
https://serverfault.com/questions/422269/where-can-i-find-the-user-in-this-iis-error-login-failed-for-user-iis-appool-w
https://archive.sap.com/discussions/thread/3650527
https://arcserve.zendesk.com/hc/en-us/articles/202044599-SQl-Autodiscovery-Fails-with-Unable-to-connect-SQL-instance-Error-Message-