Unable to join friend's worlds when on LAN/same wifi

When attempting to join a friends world on the same wifi, suddenly I cannot connect. 

This isn't a problem when on different wifi, and hasn't been a problem because of platform differences - iOS and Windows. Whenever we are connected to the same wifi, I can see the world, and click to join, however the world doesn't connect at all or I connect briefly and are kicked after a couple seconds of broken gameplay.

We make sure LAN connection is on, as well as multiplayer settings being correct. It's been a problem consistently when on the same wifi, every time.

I wanted to include some screenshots/videos of the issue however when attempting to join again, the world no longer even shows on the friends section, despite having all the correct join settings on still.