Yesterday evening, our main hypervisor didn't answer ping requests after some hours, then after mere minutes.
I provisioned during the night a new hypervisor per T1215 plans and migrated Dwellers (with success) and Ysul (see below) there.
Ysul isn't there, as when I boot the Ysul VM (or a new FreeBSD VM by the way), BIOS can't see the virtual disks.
Our ISP, Online, investigates the issue.