I’ve encountered an issue a few times when Proxmox updates Machine types with updates.
My Windows machines sometimes present errors as after updates no UUID is present. Some software’s don’t like this.

You can test this on Windows by inputting wmic path win32_computersystemproduct get uuid

Likely you may see “No Instance(s) Available.”

A quick fix I’ve found is to have a UUID set in the VM config

Going into your VM Config file
root@proxmox01:/etc/pve/qemu-server
Set the following arguments
args: -machine smbios-entry-point-type=32