Swarm agent error: Channel registration failed. Reason: Failed to create an IPC Port

Hi

I’ve set up swarm coordinator on 1 PC and agent on another but when I attempt to bake lighting in my scene UE4 hangs for ages with ‘Starting up swarm connection’ in the status dialog. I have this error in my swarm agent log: Channel registration failed. Reason: Failed to create an IPC Port

Could anyone offer some assistance?