Snapshot Backup error

Good day,

Im a VA of mr. Pol vanrhee, I have a concern about the backup we creating site backup in the wpmudev hub which is you just click the run backup and then it alls backup the site. So we have full backup of one of our target site our goal is to make sure that the backup we are generating from your tool is good and complete. So as you can see in screeshot_3 i have latest backup just last week.

I did download the file and upload it to my personal dropbox and get the url and put it into the snapshot import section which you can see in screenshot_2.. But unfortunately i got an error "Error: Manifest data not found in archive."

Hope you can help me with this.. All I want is to run a complete and good backup and test it to our test site to make sure is 100% good and running thats what im doing now.

Thank you