You receive an error 408 when you try to install VMMAgent on HyperV host machine that you would like to add to SCVMM for management.
lynchyperv.lab.com has an unsupported version of the Virtual Machine Manager agent installed.
Uninstall the Virtual Machine Manager agent using Add or Remove Programs on lynchyperv.lab.com, and then try the operation again.
First uninstall any agent on the HyperV host machine.
Then on the SCVMM Server, navigate to the following path
C:\Program Files\Microsoft System Center 2012 R2\Virtual Machine Manager\agents\amd64
Copy the folder 3.2.7895.0 to the Host machine that you want to add it to the VMM server and run to install the agent and try again to add the agent.
As in the below snapshot .. this will work for you