I was setting up a debian VM, while doing that I had to go away for some time. When I came back I noticed the vnc got disconnected tried to reconnect but it wasn't working, and I wasn't able to get on the vm page. 

I disables/enabled tha vm manager and then I got the "Libvirt Service failed to start". 
Those are the logs:
 

2023-01-21 15:03:15.122+0000: 14279: warning : qemuDomainObjTaintMsg:6602 : Domain id=2 name='Home Assistant' uuid=f1aed52f-1a57-fc99-ce68-5b3bcb4c7bcb is tainted: custom-ga-command
2023-01-21 15:03:15.353+0000: 14278: error : qemuDomainAgentAvailable:8610 : Guest agent is not responding: QEMU guest agent is not connected
2023-01-21 15:03:15.441+0000: 14278: error : qemuDomainAgentAvailable:8610 : Guest agent is not responding: QEMU guest agent is not connected

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lot's of repeating the same thing... (that isn't a log)
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2023-01-21 16:57:24.469+0000: 44507: warning : qemuDomainObjBeginJobInternal:909 : Cannot start job (modify, none, none) in API remoteDispatchDomainShutdown for domain Dynmap webserver; current job is (query, none, none) owned by (14279 remoteDispatchDomainGetBlockInfo, 0 <null>, 0 <null> (flags=0x0)) for (749s, 0s, 0s)
2023-01-21 16:57:24.469+0000: 44507: error : qemuDomainObjBeginJobInternal:944 : Timed out during operation: cannot acquire state change lock (held by monitor=remoteDispatchDomainGetBlockInfo)
2023-01-21 16:58:19.749+0000: 51164: error : qemuMonitorIORead:440 : Unable to read from monitor: Connection reset by peer

 

arialis-mserver-diagnostics-20230121-1829.zip

A restart fixed it.