If you have one phone that doesn't work properly, please try the following steps.
1. Reboot the phone. Many times this will clear the issue and the phone will start working again. If you have to reboot frequently, contact us for further troubleshooting advice.
2. Check the cable connections on the back. The cable from your network wall jack must connect only to the phone port marked "LAN" or "SW." There may be a cable from the PC port to your computer, or not. However the PC port can never be used to connect the phone to the wall. If the cables are reversed, things will appear normal however the phone can't make or receive calls.
3. Try connecting the phone in another office where there is an existing phone that is working. This will eliminate the cabling and in-office connections as a potential problem. If the phone works in another office, then your network administrator will need to check the cabling connections in the non-working office.
4. If you are using any kind of wireless devices between the phone and main router, such as wireless bridges, please test the phone connected directly to your main router.
5. If a phone continually goes into a state where it can call out but nobody can call it, the router it is connected to has a problem with its NAT settings or capabilities. We can help with some suggestions, but in many cases the router will have to be replaced. This particularly happens with older and/or cheap routers on home networks.
If none of this helps, please tell us if there are any error messages on the display, and what lights, if any, are on. Feel free to attach a photo of the phone display if that's convenient. Please note the color of the line button display as shown below (green or red).