Phone: iPhone 6

iOS: 12.3.1

Signal: 4G, 2-4 bars all time. Tried WiFi too with full signal power.

Step 1) Go to Campaign, Kaerok Castle, Stage 6. (currently doing Hard Mode for Challenges).

Step 2) Select heroes I want, Maxed attacker and 3 low levels to level up. 

Step 3) Attack / Replay, wait for page for loading bar. 

This is where it happens, right before the stage loads the game just closes and crashes. This involves me losing the energy.

This has happened on other loading areas like Clan Boss (Loss of an attack key).

As well as even sometimes just going back to home page it can crash (this has only happened twice).

I've played this game for about 2-3 weeks now. There are times when I can play for 30-60+ minutes at a time and there is no crashes but recently they have become more and more common crashes and was wondering if anyone knew how to fix this?

Tried restarting phone and reinstalling app.