Joining issue

It's been 2 days since I've been trying to join a multiplayer game, I've reseted my internet, powered off my phone, deleted and redownloaded Minecraft but it doesn't allow me to join my friends. I join my own worlds and invite my friends, but then they can't join. I've checked all of my settings to make sure everything is enabled and it is? I would really like to join my friends and I'm just missing out on a ton. Thank you!