Hi All, We have a 3CX v15 Linux system hosted on an OVH VPS server. We have 4 Yealink desk phones in the office connected as direct SIP extensions (3 x T22 and 1 x T26). When one extension calls another the called extension rings but when picked up there is no audio. We also have some extensions registered to the 3CX client on PCs and Mobiles connected on the same network. If a Yealink phone calls one of those extensions there is audio. Also if one of the Yealink phones transfers an external call to another Yealink phone there is audio when doing an attended transfer. We've been using and configuring 3CX for some time but have never experienced this situation, is anyone able to point us in the right direction to resolve this issue? Thanks in advance for your assistance.