HOTSPOT
Your network contains an Active Directory domain named contoso.com. The domain
contains two servers named Server1 and Server2 that run Windows Server 2012 R2. The
servers have the Hyper-V server role installed.
A certification authority (CA) is available on the network.
A virtual machine named vml.contoso.com is replicated from Server1 to Server2. A virtual
machine named vm2.contoso.com is replicated from Server2 to Server1.
You need to configure Hyper-V to encrypt the replication of the virtual machines.
Which common name should you use for the certificates on each server?
To answer, configure the appropriate common name for the certificate on each server in the answer area.
Answer: 
Explanation:
If the virtual machine is hosted by a standalone server, the subject common name (CN) must be equal to (or the subject alternative name—DNS name) should contain the FQDN of the host. If the virtual machine is hosted by a failover cluster, the subject common name (CN) must be equal to (or the subject alternative name—DNS name) should contain the FQDN of the Hyper-V Replica Broker.
https://technet.microsoft.com/en-us/library/jj134153.aspx#BKMK_1_5
the certificate must contain the host’s FQDN (server1 will be server1.contoso.com, server2 will be server2.contoso.com)