Unable to connect to world - from IOS to IOS

My friend and I bought Minecraft pocket edition for several days now. We have the same version of Minecraft. She's opening from iPhone xs and I would be playing with iPad pro. The problem is I can't join her world; it would only say unable to connect to world. Only after 100+ tries of trying to connect, I would be able to join once. Please help. We didn't pay money just for it to decorate our phones. Thank you.