There could be a few reasons why the 4G Starlight Camera failed to connect. Try the following:

1. If you are in the United States:

• Make sure you are only using an EIOTCLUB prepaid 4G LTE cellular SIM card or AT&T Tablet And Hotspot Plan for prepaid data-only SIM card. 
• Check the balance on the card.

Note: if you are not in the United States, please refer to the 4G Starlight Camera SIM Card Guide

2. Hold SYNC for 2 seconds to reactivate the camera.
3. Press SYNC 5 times to try restarting the camera.
4. Insert the 4G Starlight Camera SIM card into your phone, and check if your phone has a strong network signal. If not, please choose another place with a stronger network signal to pair.
5. Check the APN information: How to configure the APN information on the 4G Starlight Camera?