My friend cannot play in my Realm world. When he tries to, he is faced with a screen saying ''you are not whitelisted on this server''.

Put the summary of the bug you're having here

What I expected to happen was...:
**

My friend should be able to join it fine

What actually happened was...:

He couldn't, and was faced with a screen that said ''you are not whitelisted on this server''

I tried to google and search for a solution, but nothing worked. I can join my world with no problem and we use the same wifi and he has been able to join it before with no problems.