Finally found a solution/explanation to the Event ID 5050, Source IAS that reads “The description for Event ID ( 5050 ) in source ( IAS ) cannot be found. Apparently this is A LDAP connection with domain controller <domain controller name> for domain <domain name> is established. and therefore nothing to worry about. It’s taken ages to track this down – I wasn’t able to find it on eventid for quite a while, but this morning it was there.