line-of-sight cartesian form

Hello community,

I was trying to calculale los2 using cartesian coordinates but it seems it is not possible

tx = txsite("cartesian", ...
    "AntennaPosition",[2; 5; 6;], ...
    'TransmitterFrequency',5e9);

rx = rxsite("cartesian", ...
    "AntennaPosition",[20; 20; 20;], ...
    "AntennaAngle",[0;90]);

los2(tx, rx)

Error

Click on the map for point 1

Error using gcm (line 25)

Not a map axes.

Error in inputm (line 44)

gcm(hndl);

Error in los2 (line 139)

[lat1,lon1] = inputm(1);