Looking for logging into the Could Not Sign In 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 Could Not Sign In site. After that you can login as usual with your login credentials.
https://apple.stackexchange.com/questions/300514/i-receive-a-could-not-sign-in-error-after-upgrade-to-ios-11-0
https://discussions.apple.com/thread/7859571
https://www.tenorshare.com/apple-tv-repair/how-to-fix-apple-tv-stuck-on-could-not-sign-in.html
https://support.imazing.com/hc/en-us/articles/115001250554-Restore-a-backup-A-server-problem-is-blocking-Apple-ID-sign-in-
https://support.google.com/accounts/troubleshooter/2402620?hl=en
https://appletoolbox.com/2018/01/error-connecting-apple-id-verification-failed-how-to-fix/
https://www.imobie.com/support/fix-icloud-sign-in-error-on-iphone.htm
https://help.netflix.com/en/node/66143
https://stackoverflow.com/questions/44017487/apple-id-not-logging-in-xcode
https://support.bluestacks.com/hc/en-us/articles/208255433-What-should-I-do-if-I-cannot-login-sign-in-on-BlueStacks-
https://help.uber.com/riders/section/i-cant-sign-in-or-request-a-ride?nodeId=6ba85d9a-e865-4665-b3b9-be994fb3be28
https://www.makeuseof.com/tag/common-icloud-problems/
https://www.facebook.com/help/105487009541643?helpref=topq