Merge pull request #176836 from zoran-rilak-msft/zoran-rilak-msft-patch-1

No '@' in logins

Author: PRMerger17

articles/azure-sql/managed-instance/doc-changes-updates-known-issues.md

@@ -22,6 +22,7 @@ This article lists the currently known issues with [Azure SQL Managed Instance](
 
 |Issue  |Date discovered  |Status  |Date resolved  |
 |---------|---------|---------|---------|
+|[When using SQL Server authentication, usernames with '@' are not supported](#when-using-sql-server-authentication-usernames-with--are-not-supported)|Oct 2021|||
 |[Misleading error message on Azure portal suggesting recreation of the Service Principal](#misleading-error-message-on-azure-portal-suggesting-recreation-of-the-service-principal)|Sep 2021|||
 |[Changing the connection type does not affect connections through the failover group endpoint](#changing-the-connection-type-does-not-affect-connections-through-the-failover-group-endpoint)|Jan 2021|Has Workaround||
 |[Procedure sp_send_dbmail may transiently fail when @query parameter is used](#procedure-sp_send_dbmail-may-transiently-fail-when--parameter-is-used)|Jan 2021|Has Workaround||
@@ -311,6 +312,10 @@ using (var scope = new TransactionScope())
 
 ## No resolution
 
+### When using SQL Server authentication, usernames with '@' are not supported
+
+Usernames that contain the '@' symbol in the middle (e.g. 'abc@xy') are not able to login using SQL Server authentication.
+
 ### Misleading error message on Azure portal suggesting recreation of the Service Principal
 
 _Active Directory admin_ blade of Azure portal for Azure SQL Managed Instance may be showing the following error message even though Service Principal already exists: