Can't join servers or my friends world's in minecraft pe

I checked everything... My local multiplayer switch in on, We're both connected to the same wifi, my house has good internet, same Minecraft version but I still can't join him or other external servers even though my friend can join my worlds and servers when he is right next to me. But I think I found the problem. I went to me and friend's iPad settings and went to Wifi. It caught my eye when I saw my IP address was different to his. I tried changing it to his IP address but after that I couldn't connect to my Optus internet. Plz help me.

Even though I have the life boat app and go to open servers, I still can't join