Black screen in mobile app

I can't exactly pinpoint exactly when it started happening, but sometime earlier in the month of June between the 5th and 14th, whenever I opened the mobile app, League Friends, I get a completely black screen. I've had the app ever since it came out and it has been working perfectly up until this point. Not sure why. I sent an email to Riot Games Player Support, and someone tried to help me but they're not sure what the problem is either. Thus, they recommended submitting a bug report here. If anyone could help me, I'd greatly appreciate it!

My phone is a LG G2 and I'm using an android OS.