Login failed for user Reason: Token-based server access validation failed with an infrastructure error Login lacks Connect SQL permission. Login failed for user ‘localhost\windows_user’. Reason: Token-based server access validation failed with an infrastructure error. Login lacks Connect SQL permission. [CLIENT: <local machine>] Check you have permission to the user, generally we will have permission. Check you are able to access SSMS local & remote. Most of the case issue will be – Check how many group has deny permission, definitely your login will be one of in the group. For our case it was built in user group. SELECT sp.[name],sp.type_desc FROM sys.server_principals sp INNER JOIN sys.server_permissions PERM ON…