My calls to some countries like Australia for e.g cannot hear the called party. But some calls have no issue. This is major irritant in using zoiper for me now.
The codec settings audio for my sip account is u-law.
I have tried various recommendations mentioned by your pages on no audio or one way audio without results.
My provider has mentioned that there is this line which shows up on the asterisk logs "res_rtp_asterisk.c: Unknown RTP codec 95 received from "
Please help to resolve this issue.