If the Electronic Program Guide (EPG) is not loading on an IPTV app on a Firestick, there could be several possible causes:

1. **Insufficient Memory/CPU**: Firestick devices have limited hardware resources, and if too many apps are running at the same time, this could cause the EPG to fail to load.

2. **Network Issues**: If your Firestick is not able to establish a stable internet connection, it may not be able to download the EPG data.

3. **App Incompatibility**: The IPTV app itself might have some compatibility issues with the Firestick or the specific version of the operating system it’s running on.

4. **Corrupted App Cache/Data**: Sometimes, corrupted cache or data can cause apps to behave unexpectedly. Clearing the cache and data might solve the problem.

5. **Outdated App Version**: If the app is outdated, it might not function properly. Make sure the app is updated to the latest version.

6. **VPN Interference**: If you are using a VPN, it could cause delays or restrictions in loading the EPG data.

7. **Incorrect EPG URL**: If you have to manually input an EPG URL, make sure it is correct and in the right format.

8. **Software Glitches**: Sometimes a simple restart of the Firestick or the app can resolve transient software glitches that may prevent the EPG from loading.

9. **Firewall or Security Software**: Sometimes, security settings can block certain network traffic, interfering with the ability to download or display the EPG. Using a VPN can fix this issue.

10. **Use of a Dedicated IPTV Box**: It’s important to note that using a dedicated box for IPTV is generally far superior to using a Firestick or other small devices with limited memory. These dedicated boxes are specially designed to handle IPTV and typically have better performance and more resources, reducing issues related to EPG loading.

By considering these various factors, you’ll be better equipped to identify and resolve potential issues related to your EPG’s loading.