Yesterday I ran into a strange situation. Users started telling that thay were not able to connect to their application using the sql account 'abcacc'. I checked logs and found several login failures from this account. When checking login property, it threw me error "Property IsLocked is not available for Login '[abcacc]'. This property may not exist for this object, or may not be retrievable due to insufficient access rights. (Microsoft.SqlServer.Smo)". I googled about it and executed below t-sql.
alter login abcacc with check_policy = off,check_expiration = off
Consequently, it started making successfull connections from this account. Gradually same issue was faced for other sql accounts on the instance and I executed the same script. Please note account was not locked.
Later 'Stack Dump' error was observed in the log just before the login failures started. Can someone please help me understand that above error came due to memory pressure or there could be other reasons as well? Wanted to know the root cause to avoid this issue in future.
Thanks in advance.