RFXCOM Setup

Hello, I’ve recently picked up “from a well known auction site” a RFXCom Universal Transceiver, (The black box one with an ethernet port). I have successfully set up the network side of it, but am having trouble getting openhab to talk to it.
I have installed the rfx binding and added the following thing.

Bridge rfxcom:tcpbridge:sunflower [ host="192.168.101.237", port=10001 ] {   
}

Paper UI just reports “Offline - communication error” and the tail logs:

2021-01-18 20:28:50.367 [INFO ] [nternal.connector.RFXComTcpConnector] - Connecting to RFXCOM at 192.168.101.237:10001 over TCP/IP

2021-01-18 20:29:42.774 [ERROR] [internal.handler.RFXComBridgeHandler] - Error occurred: Timeout during packet read

My openhab installation runs within a docker container running on a synology nas.

Can anybody assist.

Regards

Anthony