vNetwork Distributed Switch (vDS) proxy switch port is unavailable.
This might occur as part of VM power on, or if the user attempts to connect a VM's vNIC to a dvPortgroup or a dvPort.
The message will contain the vNIC MAC address, the UID of the vDS, and the port number.
Migrate the virtual machine to a different host. If this is a vendor-specific vDS, consult the vendor documentation for this issue.
Refer to this VMware KB article for more information.
Refer to the VMware Online Documentation for more information on vCenter event messages and possible solutions.