1) Make sure your SIM card is a mobile data card.
If no SIM card is detected, power off your router, reinsert the SIM card and try again.
If a PIN is required, enter the PIN and try again.
If no service is available, move the device to an area with a better signal (try placing it near a window) and try again.
2) Log in to the Home page (Refer to "How can I access the Home page?" in the Basic Settings module). Click Status to view the connection status.
3) Log in to the Home page (Refer to "How can I access the Home page?" in the Basic Settings module). Go to the Home page, click "Disable Mobile Data" and "Enable Mobile Data" buttons to restore your network connection.
4) Restart your router and try again.
5) Reset your router and try again.
6) If MAC address filtering is enabled, make sure your device’s MAC address is on the approved list.
7) If Parental Control is enabled, make sure your device name and MAC address are not under parental control.

Note: Available settings and menus may vary depending on device model and software version.