Hi, thanks for all input.
Tried tonight all suggestions, without any luck :-(.
Used solar cell which produces around 6.0V in combination with the USB.
Found the possible cause of the problem, check the voltage of pins 45/46 of the BC95B module, which was about 2.7V. While the specifications ask for more....
Checked also the 8211.json file, this one is referring to the M35 module. Not sure if this might be the problem, the pin definitions of the NRF52 seems to be ok...not sure at the BC95B module.
Any final ideas are welcome.. :-(