The first thing to check is the Veeam Virtualization Extensions Web UI - check if you can see your Hyper-V server there. If you cannot - click on "Update Monitored Hosts". If you still cannot see your Hyper-V servers - make sure that SCOM agents are installed and discovered on those servers and then click "Test OM SDK Connection" in the Web UI to see if there are any issues with SCOM API connection.
Also make sure that Proxying is enabled for SCOM agents installed on Hyper-V servers.
If everything is OK (Hyper-V servers are discovered as Widnows Servers in SCOM, you can see them in our Web UI and they are enabled for monitoring, agent proxy is enabled), but you still don't see Hyper-V server objects discovered by Veeam - I would recommend to open a support ticket, becuase we will need log files (both collected using our Web UI and from Operations Manager log on SCOM servers and agents). Our Tech Support team will do their best to resolve the issue promptly, we have a great team of engineers there.
Let me know if you have any other questions.
Thanks you very much for your interest in our Hyper-V product. I hope we can solve the issue asap, so that you can use it at full power.