To solve the issue follow the advice on this link:
"I ended up copying the msg723.acm file from a Windows 2003 Server, dropped
the call recordings.
Indeed it works much better now. I have this kind of file generated a voice recording in Altigen MaxACD Call center WAV G.723.1 ((khz, 8bit, Mono, 0.8kb/sec)
the other choice is WAV GSM and WAV PCM. The latter can be played in Media Player out of the box.