Mobvoi TM Incline Android Connection lost


I’m new with the app an the treadmill (Mobvoi TM Incline).
First I was connecting my treadmill to a Win11 PC and everything is working fine.

Now I want o use ZWIFT with the Android phone and I’m running into problems.
I can connect an everything looks good. But the app will not show the speed of the treadmill.

The treadmill is only connect to one of the system. Bluetooth is off on the Win PC.

Is it a known problem? How can I solve it?
Thank you.