Looking for logging into the Created Site Collection 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 Created Site Collection Failed site. After that you can login as usual with your login credentials.
https://social.technet.microsoft.com/Forums/sharepoint/en-US/dc1e16a0-b90e-44de-9ae8-95ddb3930a3a/cant-login-to-newly-created-site-collection?forum=sharepointgenerallegacy
https://sharepoint.stackexchange.com/questions/18515/add-login-account-to-access-wss-content
https://sharepoint.stackexchange.com/questions/57758/not-able-to-delete-site-collection-using-powershell
https://community.spiceworks.com/topic/658169-sharepoint-2013-cannot-delete-site-collection-due-to-sql-login-failure
https://stackoverflow.com/questions/1728730/login-to-sharepoint-web-application-fails
https://www.metalogix.com/help/Content%20Matrix%20Console/SharePoint%20Edition/004_FAQ/028_SP2013SiteCollectionCreation.htm
https://support.office.com/en-us/article/troubleshoot-site-collection-upgrade-issues-95e30367-f099-424e-ab50-0833919b0e91
https://support-desktop.sharegate.com/hc/en-us/articles/115000643328-The-connection-with-the-SharePoint-site-failed
https://www.toddklindt.com/blog/Lists/Posts/Post.aspx?ID=154
https://jcallaghan.com/2014/02/error-when-creating-new-site-collections-via-central-administration/
https://www.c5insight.com/Resources/Blog/tabid/148/entryid/275/sharepoint-login-issues-how-to-fix-users-who-cant-log-in-via-their-user-principle-name-upn.aspx
https://blog.kloud.com.au/2017/08/10/sharepoint-online-external-user-access-error-user-not-in-directory/
http://www.sharepointdiary.com/2014/10/cannot-open-database-requsted-by-the-login-login-failed-for-user.html