Transcoding from g711 to speex

[Mike 3CX]

I have been trying to connect several extensions local and remote on my 3cx free server to Voip provider and transcode from g711 on the provider side to speex on the extensions side, on the extensions sides I cant hear the voip side, on the voip side I can hear both side, my pbx deliver audio is checked, all firewalls are open, even with the tunneling I have the same issue, I installed 3cx on another machine to check if it is my Pc but I am having the same results. But transcoding from and to g711 to g722 works perfect, on the same setting.
Any thoughts please share.
Thank you

 

[leejor]

What make/model extensions are you using? What does the 3CX log show (verbatim) on a call set-up.