RFD900x to FRSky Telemetri

Dear all,
today i change the Software of a bought Copter from PX4 to Ardupilot.
As aspected for the Work I’ve to do it is working much better.

The FrSky Remote is also working over the RFD900x Datalink.
Now I got the Problem that before (under PX4) I had the Telemetry Data on the Remote and now under Ardupilot nothing shows up.
Has anyone got an Idea, what settings i got to change?
Hardwarewise i didnt change anything
Thanks in Advance