Login failed for user ‘(null)’. Reason: Not associated with a trusted SQL Server connection.

problem:

a working replication setup suddenly started failing with below error ..nothing was changed from configuration aspect of

subscriber .. but the distributor could not connect to the subscriber .. moreover .. the connection to subscriber instance (VIA windows

authentication ) could not browse through properties ETC .. (SQL agent ETC)

error :

Error messages:
The process could not connect to Subscriber ‘subscriber_instance’. (Source: MSSQL_REPL, Error number: MSSQL_REPL20084) Get help: http://help/MSSQL_REPL20084 Login failed for user ‘(null)’. Reason: Not associated with a trusted SQL Server connection. (Source: MSSQLServer, Error number: 18452) Get help: http://help/18452

Solution:

1> login failed for user ‘NULL‘ is basically solved by switching the instance authentication mode to mixed from windows

(in my case it was already so)

2> in the eventvwr .. few kerberos warning and errors were logged in (which looked every cryptic)

3> instead of troubleshooting those .. i decided to bounce the SQL instance .. to see whether it clears the error

for above scenario .. it worked fine .. and NULL user errors were no longer appearing ,replication was working fine ..

other Scenario :

4> you may to change authentication mode to mixed ..

hope this helpful to you 🙂