UI button events not working on android

After testing UI buttons int the editor and making sure they're working fine, I went ahead and deployed an APK package to my Android phone. While the buttons show the clicking animation, the functionality is simply not there. I did multiple tests and tried different solutions posted online and nothing worked for me. Here is a snapshot of my EventSystem. I tried enabling the "Force Module Active" for both Standalone and Touch input modules in all the different combinations but not avail.

And here is a snapshot of one of my Button GameObjects. I tried disabling the "Graphics Raycaster" script on the parent GameObject containing the Canvas component. I tried changing the way the function that is called through the EventTrigger attached to buttons works. The function that is called through the EventTrigger calls a function on another object if that helps. (Note: ButtonEventHandler is my script and not to be confused with Unity's Standard Assets' "ButtonHandler" script. It contains two methods that I have written with the names OnPointerDown and OnPointerUp)

It is as if the functions are not being called when the buttons get tapped on the phone. They work perfectly when clicked with a mouse in the Unity Editor.