Virtual Switch stopped responding

[hallb15]

This morning I came in to work to find no-one could access the fileserver.

When I checked the VM, it was reporting it was connected to our domain but no internet access. A quick ping test showed it could not contact anything, not even the host server.

This VM was using a new virtual switch (#5) that I created a couple of months ago when I put a new 10Gb NIC in the host server. It has been working fine up until now.

 

The 10Gb NIC is connected via fibre between two buildings to a Unifi 16XG switch which was showing as connected and working in the unifi controller.

I've checked the event log and can see when it happened, but I can't see anything obvious as to why.

 

So I stopped the VM, changed it to a different virtual switch (#3) and restarted it but the same issue happened.

So I removed the virtual switch #5 from Hyper-V and restarted the VM again, this time it connected (still on #3) and everything was fine.

So I've re-created virtual switch #5 on the 10Gb NIC and moved the VM back on to it and now it works again.

 

So, my question is has anyone else experienced similar behaviour? I don't want this to happen again.