After installation or reconfiguration of the Symantec Endpoint Protection Manager using a SQL database, it starts being logged errors of Login failed for user '<username>'.
<date> <time> Logon Error: 18456, Severity: 14, State: 5.
<date> <time> Logon Login failed for user 'srv_sepant'. [CLIENT: dotted.ip.address.]
Lack of permissions of the previous used account.
The <username> doesn't have the correct permissions in the SQL server or database.
Run Management server wizard and replaced the connection details with SQL authentication and 'sa' account and the errors should stop being logged. For using the previous account <username> the customer should assign it the correct permissions.
Differenciate Authentication failed and Authorization failed. When you saw error " Login failed for user ' ' ...." or " Login failed for user '(null)' " or " ANONMOUS LOGON", these are authentication failure. When you saw error like " Login failed for user '<username>' ", these are authorization failure, which is related to your SQL server security settings.