Engine locks up with trying to build lighting

I’m having this issue when trying to build any sort of lighting in UE4. It seems to happen regardless of the engine version.

I hit Build lighting and the engine freezes up when trying to connect to the Swarm Agent. I’ve already set my firewall to allow the Swarm agent to run so it doesn’t seem to be that.

This is the error Log i’m getting.

[ERROR] Channel registration failed. Reason: Only one usage of each socket address (protocol/network address/port) is normally permitted
, Callstack: at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Bind(EndPoint localEP)
at System.Net.Sockets.TcpListener.Start(Int32 backlog)
at System.Runtime.Remoting.Channels.ExclusiveTcpListener.Start(Boolean exclusiveAddressUse)
at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.StartListening(Object data)
at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.SetupChannel()
at Agent.AgentApplication.Main(String[] args).

Any help would be really appreciated.