Laptop VNC Connect works using WIFI, Crashes using 4G MObile Broadband

Hello,

We have a lenovo yoga notebook that can connect using vnc connect cloud subscription without issue when using a "WIFI connection". 

When I switch to using the "Mobile 4G Broadband connection" the vncviewer.exe crashes with no error message. I have tested that general internet browsing works on the mobile broadband connection.

The windows 10 firewall profile is the same for both connections (Public).

Nothing is obvious from the vncviewer.log file. But the crash is reported in windows application event viewer with nothing meaningful displayed as to the cause.

Thanks

Adam