I know this is a very old thread but I had this issue and couldn't find anything online to fix it.
Figured out today that if you remove the broker from the server manager and then add it back in, then it all comes back to life!
Not sure how I fixed it on the actual broker's Server Manager as you can't remove the server you are on... but after playing around and cleaning it out completely, that has started working again.
Hope this helps someone.
Our situation happened after migrating the broker VM from VMWare to Hyper-V which blats the NIC.