Hi all! I have just set up a new 3CX server and I am setting up the phones - Yealink T21P E2 and Yealink T41P. I am getting poor voice quality on both, and to rule out that it's the phone, I have connected a third Yealink T21P E2 to our Asterisk VoIP server and the voice quality is excellent. By "voice quality" I mean that it sounds like a very low bit-rate. I have tried the following: upgrade the firmware on both phones set the codec for the extension in 3CX to 722 only by removing all other codecs checked the web interface for the phone correctly configured the firewall - "Firewall Check" on the 3CX Dashboard reads "Firewall test ok" the phones are connecting through a VPN (for both 3CX and Asterisk) Please see attached images.