We expire registrations after 5 minutes, which is a setting that we negotiate with your phone when it registers with our service.
Some devices, the most common being Linksys, ignore the registration expiry setting that we set during registration.
If you find that your phone registers ok, but then after 5 minutes, stops receiving calls, then the most likely cause is this setting.
In the first instance, check the configuration guide for your phone (link available below) for how to log in to the phone's configuration screens. Once you are logged in, look through your account settings for a setting entitled 'Registration Expiry' or 'Register Expires' or similar. This setting is normally in seconds and should be set to 300.
Feel free to get in touch if you believe this is the issue that you're experiencing but can't find the particular setting on your device.
