Frequently disconnects from Realm server

Just bought my first realm. I have been playing in a single player world for the last few days and wanted to import it. When I created the realm it generated the random world and works fine. When I select “replace world” and upload the other world, the game will upload successfully and rather quickly but when I click play is when it gets weird. It loads with the usual text boxes, then for a few seconds it just shows the video that usually plays in the background during a loading screen, then the screen goes blank and gives me the error “disconnected from server.” The server shows up green/online on my main menu. If I delete and regenerate the world to random the Realm works again. I can still play the world I’m trying to import in single player and it loads fine, it also works online when friends connect to it.

I’ve tried updating the game, my system, clearing my Microsoft account log in and relogging but nothing works.

 

EDIT: I noticed that when I try and load into my imported world Realm that the “Loading Resources” screen is always where the game stops loading and gives me the error. My imported world I’m trying to get to work uses the Natural Texture Pack.