If your phone is showing as unregistered, no network connection, searching for network, etc., it is likely not receiving a connection to the internet.
Please check all cable connection, at the phone and your router, to make sure the network cable has not come loose or worked it way out of the network port.
On occasion, your internet service provider will renew the IP lease for each of their customer. This is common practice, and the new IP address is typically pushed to the end devices automatically. In rare occurrences this does not happen causing your IP phone to lose it's connection. Simply rebooting your network equipment (modem/router/network switches) with almost always resolve the issue, even if all other network connected devices are working properly.
For further assistance, please reach out to support@simplifi.io.