SBUS connection issue

Strange problem with the SBUS on the ZMO Pro Controller in Hobby VTOL

I am using a Herelink Tx Rx which has worked fine on a Pixhawk4 with Sbus
If you connect the SBUS from Herelink Rx to the ZMO Controller no activity, ie stick movement not being shown in Mission planner. If you Connect SBUS Herelink Rx to ToolkitRC (Sbus analyser mode) this shows its working fine. If you connect the ToolkitRC (Sbus simulator mode) to the ZMO Controller it works fine. Any thoughts or suggestions please