followme not found in C++

[larcenn00]

hello, I can't get the example program follow_me.cpp to work. In the console it displays the messages to me, with the coordinates generated in squares, but the drone remains at a static altitude of 2.5m.
I'm on Linux Ubuntu 22.04 with simulator as recommended in the mavSDK documentation.

The other examples work.

Is there anything special to do that I'm forgetting?

Thanks a lot