A SQL backup at transaction log level has the following warning:

[warn] [Microsoft][ODBC SQL Server Driver][SQL Server]The statement BACKUP LOG is not allowed while the recovery model is SIMPLE. Use BACKUP DATABASE or change the recovery model using ALTER DATABASE. 


The error is occurring because the SQL database has been setup in 'SIMPLE' recovery model.
In this mode, SQL does not use transaction logs in the same way as the full recovery model, so you cannot run transaction log only backups.


To resolve, you can adjust the recovery model of the database as described in the error from simple to full or bulk logged

Alternatively, you can just adjust the schedule of the backup set to run a Database level backup every day, rather than transaction log backup jobs (may not be practical for bigger databases)