Backup creation failed on Plesk 11.5 for Windows with error:
Cannot open database "my_db_name" requested by the login. The login failed. Login failed for user 'NT AUTHORITY\SYSTEM'.
MSSQL user does not have proper permissions for database "my_db_name".
Go to SQL Server -> Security -> Logins and right click on NT AUTHORITY\NETWORK SERVICE and select Properties.
- In newly opened screen of Login Properties, go to the "User Mapping" tab
- Select the "my_db_name" database
- Then set the role as
db_ownerand Click OK.