Backup module issues

I have a large number of version 14 & 15 systems installed in a cloud system. They all work well. I have setup a S3 bucket to save Backup files. I use an Rclone script along with cron to move the backup file. The script also emails me when there isn’t a file to move. I know about Filestore and the s3 connection there. It just didn’t work fo rme. Anyway the question of the day is: What would occasionally keep the backup (Freepbx module) from running? I will have a couple of systems a month that do not produce a backup file. If I go in and manually start the backup it works fine. The Rclone script when run manually moves the file as it should. Could there be a process that would stop the backup from running ??

Thanks