First question has to be - are there actually VMs running on that Host? (Sorry, but it has to be asked
If there are VMs running there - can you see them in SCOM views? Have they been discovered (for example, All VMs state view)?
If you open a Diagram view for this Host (or, browse the Compute topology) - can you see those VMs under the host VM container?
If the VMs are missing from SCOM, or the container, then the first thing to try is Rebuild Topology - you can find this as a link in our Veeam UI, or also as a Task in-context of Collector in the SCOM console.
Once rebuild process is complete (wait at least 30 minutes) then check for those VMs again.
Let us know if that helps!