We just transitioned to VOIP with the 3CX system. We've got SPA514G voip phones on Firmware 7.5.5. If a user is on a call, and another call comes in, the second line key doesn't do anything. I've tried some things in the phone's configuration web UI which didn't work, and I've tried reading the manual but I can't make sense of it because I'm very new with this.
What do I need to do to enable those keys to work for incoming calls? Let me know if there is any other information you need from me.