Fix SSO sign-in and non-routable domain issues

https://techdirectarchive.com/2020/07/22/how-to-fix-sign-in-issues-non-routable-domain-invalid-usernames-and-passwords-for-sso/

#ADConnect, #Azure, #AzureAD, #AzureADTenant, #EnableAzureSingleSign-On, #FixAzureInvalidUsernameAndPassword, #FixNon-RoutableDomainsIssueForAzure, #FixSign-inIssues, #FixSSOIssuesForAzure, #Login, #MicrosoftAzureActiveDirectory, #MicrosoftOnlinePasswordReset, #Pass-ThroughAuthentication, #PTA, #Slide, #UserAccess, #Username, #Users