Thanks for that. We should leave that ticket to Technical Support I think.
In the meantime, I note you stating that local backups do work, and, you don't have any valid backups right now with this remote issue. If you haven't yet, I'd switch back to local if possible, for obvious reasons.
If it was me, I'd rename cpbackup directory (local) and generate fresh backups (if you can afford the space). Just to be sure I have up to date backups without issues. Once I was sure I had those, kill that renamed cpbackup directory.