This usually would indicate that the correct credentials need to be set on the SQL Plugin. Either the credentials have not been set yet, wrong, or may have been changed on the SQL side, so the plugin cannot authenticate to the SQL instance to do the backup.
This usually would indicate that the correct credentials need to be set on the SQL Plugin. Either the credentials have not been set yet, wrong, or may have been changed on the SQL side, so the plugin cannot authenticate to the SQL instance to do the backup.