We used to use ghost for imaging student labs using multicasting. We are switching over to using zcm for imaging of these labs. However when I try to launch a multicast session I get the message above on each client saying "Waiting for session master to start" but nothing happens.

Ghost multicasting is working so not sure what is wrong with ZCM. The version of ZCM is 10.3A. Zenworks Imaging Agent ver is

If ghost is working then can it still be a switch/config issue, or is this a ZCM server issue? Thanks.