My MCPE world is crashing when I'm trying to play with add ons

I recently played Minecraft: Pocket Edition on my Apple iPad (6th Generation) in my city. After playing in my city, I downloaded some add-ons from the website https://mcpedl.com because I wanted to have more city build things in my world. But when I'm activating an add-on (with resource pack and behavior packs), my world crashes without a crash report. It occurs with every Minecraft: Pocket Edition add-on (the add-on size (in bytes) isn't important here). I'm going to be very happy when it's fixed because I wanted to play with add-ons in my Minecraft: Pocket Edition city build world.