Checking the folder that is set in Filestore /var/spoo/asterisk/backup the backup files are there. Is there a missing setting to go to the correct folder?
This does not answer your question, but you could just download the files using something like WinSCP. Not sure on the error. You might need to submit a bug report.
Comtech
This issue is for the local user, we don’t allow them to get under the hood. I did find a thread that you commented on re: In 15 the module puts a failed backup in a different folder than the one used for download. I believe now that is what is happening.