XIAO SAMD21 USB Serial issue on Android


I am trying to connect XIAO SAMD board to 3rd party app to communicate as Serial USB.
The app is Realdash. The code being used is this: RealDash-extras/RealDash-CAN at master · janimm/RealDash-extras · GitHub

The problem - when this code is running with Serial Console, it works ok, and serial communication is initialized. However, when the XIAO is connected to Android device, it is not recognized as Serial Device. As a consequence, the “permission dialog” is not shown, and app is failing to use the USB due to lack of permission.

Same is being discussed in that forum. Seeeduino XIAO SAMD21 Realdash-CAN not working on Android - RealDash Forum

Is my code wrong, or there is a Serial USB driver issue on android devices?

Any idea what could be the issue?