There could be various reasons why live video streaming works with Wi-Fi but not with 3G/4G/5G while using the AiCam app (which uses WebRTC for live video streaming). Some possible reasons are:

1. Network speed and stability: Wi-Fi usually offers higher network speeds and greater stability compared to cellular networks like 3G/4G, which can result in a better video connection. It's possible that the user's cellular data connection is not strong enough to support WebRTC video.

2. Firewall restrictions: Sometimes cellular network providers block certain ports or protocols used by WebRTC, which can hinder proper connectivity. On the other hand, Wi-Fi may not have such restrictions.

3. Quality of Service (QoS) settings: Cellular networks may have stricter QoS settings applied to data traffic compared to Wi-Fi, which can lead to delays and packet loss in video transmission. This can adversely affect the quality of the video stream.

4. Device compatibility: Another possibility is that the user's device might not be compatible with the specific combination of WebRTC implementation being used along with the cellular network provider's configuration.

To resolve this issue, you can try the following steps:

- Check if the cellular network signal strength is sufficient for video calling.
- Try using a different 3G/4G/LTE to see if that solves the problem.
- Ensure that there are no firewall/port restrictions from the cellular network service provider.
- Test video streaming with another device on the same cellular network to see if the issue persists.