The RTP relay was on, but finally I managed to solve this. I swotched the Port mapping under SIP Server Admin/RTP from source port to sdp.
The Brekeke PBX and the Linphones on an android ...
First it appeared under Blocked IP Address, but now it is woking. The bad new is if I make a call from one Linphone to an another one the voice is not working either from one side or from the other on ...