hi heiner,
Everything is OK now. it was this file : m2p_rpi3_7zoll_232.img. when I tried m2p_rpi_default_244_wps_ap_expand.img it was good.
I can stream squeezilite to my BT speakers now (UE BOOM).
Sometimes I lose my BT connection with the speakers. I need to reboot the rpi 3 and it’s ok.
Ill try an USB BT Stick and see what happens.