I had it working previously. Same themes, same host.

Now it takes ages to make a backup and when that is uploaded, the plugin does not recognise the upload. I've tried multiple times with .zip and other formats.

Simply put - this is genuinely a waste of time. Support documentation is ambiguous (which site is the donor if you're cloning a site).. completely ambiguous.

Sadly I can't give this a zero. Software that is designed to be simple.. should be.