When some of my friends join my realm, their game closes.

When some of my friends try to join my Bedrock realm, their game crashes right when they join. If your in the game, you can see them join and leave. Most are on pocket, but one is on Windows 10. It is an issue with the world itself, because I have tried hosting the world in different ways and it didn't work. I have been trying to fix this issue for weeks, please help The attached video is one of my friends having the issue.