1. Ensure that Cosmos 4K SE and the router are within 5 meters of each other and that your other devices can detect the Wi-Fi signal.

2. Confirm that your other devices are connected to the same Wi-Fi network.

3. Check if your time zone is accurate by going to Settings > System > Date and Time.

4. Try connecting to a different Wi-Fi network or use your phone's hotspot.

5. Experiment with your router's 2.4 GHz and 5 GHz settings.

6. Disable other wireless devices such as Bluetooth and wireless mice, as they may interfere with the Wi-Fi signal.

7. Reset the router's settings.

8. Restart your projector by going to Settings > System > Restart.

If the above solutions cannot solve your issue, please contact Nebula Customer Support at support@seenebula.com for further assistance.