Zwift Companion does not control resistance on the TACX Flow Smart

I am using the TACX Flow Smart trainer.
When I want to use Zwift PC and Zwift Companion as a Bluetooth receiver on my ASUS ZenFone 3 Max (ZC553KL) phone, the trainer’s resistance control doesn’t work. (cannot connect). Other connections, power, cadence, heartbeat, work.
Interestingly - When I launch Zwift on Android on my phone, all connections from the transmitters work (power, cadence, resistance, heartbeat).
Also something is wrong with Zwift Companion.
Best regards and please solve the problem. Stay healthy. Robert.