This issue has already been resolved, and I'm writing for general knowledge about the resolution and for any insight regarding the cause of this issue. I received a complaint regarding the Grandstream system, which had no audio issues between analog phone calls, but experienced one-way audio with Wave users. After a reboot, the analog phones could neither dial nor receive calls. I checked the extension settings, changed the RTP ports, and verified that the codec was set to G.711, but none of these changes worked, and nothing else appeared to be wrong. Ultimately, I decided to reset the gateway. After resetting the gateway and recreating the extension and UCM details, the calls started to connect, and the dialing issue was resolved.