In my company we have a oVirt 4.5.4-1.el9 running and a Vinchin Backup & Recovery 8.0 as a backup  solution.

A strange situation. Same VM's stopping working, frozen, when the snaphost it is been removing. And when this happened we must kill the process directly in the host because we can't do this on oVirt web management.

I just found some information on message log, notting on vdsm or libvirt logs. Here what is in the message log:

Aug 13 21:49:26 HOST libvirtd[5304]: Cannot start job (modify, none, none) in API remoteDispatchDomainSetSchedulerParameters for domain VM; current job is (query, none, none) owned by (5332 remoteDispatchConnectGetAllDomainStats, 0 <null>, 0 <null> (flags=0x0)) for (45s, 0s, 0s)
Aug 13 21:49:56 HOST libvirtd[5304]: Cannot start job (modify, none, none) in API remoteDispatchDomainSetSchedulerParameters for domain VM; current job is (query, none, none) owned by (5332 remoteDispatchConnectGetAllDomainStats, 0 <null>, 0 <null> (flags=0x0)) for (75s, 0s, 0s)