Okay so you are using the same port twice based on what you said. You need to resolve it using one of the following ways:
Use port 8080 for the interval program:
I assume: your end goal is to get the mobile app working from anywhere, correct?
If so, you want the interval program to launch with port 8080 and leave Apache to continue doing it’s thing.
You would use your RPi’s LAN IP and the port 8080 when installing.
Disable Apache:
If your goal is to access the interval program from anywhere and subsequently have the ability to use Ray’s hosted mobile app, which also works anywhere than you can just disable Apache.
This can be done by removing it from runtime, uninstalling it, or changing it’s port.