Xert Workoutplayer not controlling Elite Direto

so I wanted to get back on my trusted Elite Direto using the Xert Player on my Samsung Galaxy S 9 DUOS.
The combination had already worked well, but now Ive got a problem whenever I try to run a Workout.
All devices are detected on ANT+(BLE is turned off) an I even get Power Numbers when I start an activity. When I start the workout though, the actual Power drops to 0 after about 10 seconds in. Target power is displayed correctely.
Trainer Control for the Direto is of course activated.
So what could be wrong?