Az,
Is there a Firewall the RTP and SIP traffic passes through that could be the cause of these problems? Have you tried using the pcap trace function from the phone's Web UI to analyze the issues? Is the one way audio inbound or outbound?
https://service.snom.com/display/wiki/How+to+get+a+PCAP+trace+from+a+desktop+phone
https://service.snom.com/pages/viewpage.action?pageId=27886159
Regards,
Snom Support
AbdulAziz
Dear,
I have this issue in D712;-
Regards,
Az