Can join friends worlds

I am not able to join my friends world nor can they join mine. We are able to join each others realms via code. But Everytime we try join, a message comes up saying unable to connect to world.This has been going on ever since "New Minecraft" has come out and I know that this issue is happening to countless people. Please try fix this bug it would make this game 1000x better.

If it helps a good optional way to join friends come be via code. Thanks and would love to see this bug gone.