Event ID: 3041 BACKUP failed to complete the command BACKUP LOG <database name>

Issue:
Error in Application log:
Event ID: 3041 BACKUP failed to complete the command BACKUP LOG <databasename>. Check the backup application log for detailed messages.
Source: MSSQL$SQLEXPRESS

Cause:
This issue happens when the db-backupoperator does not have backup permission on the problematic database. Follow the below procedure the solve the issue.

Solution:

1. Login to the server were the above mentioned problematic database is installed.
2. Open SQL Server management studio (SSMS) and login as domain Admin.
3. Then expand the Security folder > Expand Logins then select and right click NT AUTHORITY/SYSTEM account > click properties.
4. On the properties tab select User Mapping > click problematic database and put a check mark > then select 'db-backupoperator' and put a tick mark, click Ok. See the example screenshot below.
5. Close the SSMS  console.