Backup & Restore Dropbox allows 3 archive methods:
1. TarGz archive
2. Zip Shell
3. Default Zip archive.
If during the backup process the plugin displays notification like: “Testing of TarGz was finished successfully” and does not move on or there is no logs at all, or your backup fails, stop the backup and select another backup method, for instance, “Zip Shell” or default Zip archive.
It is possible that you face this problem because your hosing does not support TarGz archive method.