The job failed. The owner (pc\user) of job FULL DB BACKUP does not have server access
Try to create the PC\user as a login and give him the backup privilege in your database with this code.

USE [master]
GO
CREATE LOGIN [SERVER\Test1] FROM WINDOWS WITH DEFAULT_DATABASE=[master]
GO
USE [mydb]
GO
CREATE USER [SERVER\Test1] FOR LOGIN [SERVER\Test1]
GO
ALTER ROLE [db_backupoperator] ADD MEMBER [SERVER\Test1]
GO