Current Events > How do you add someone to a private room?

(+) Yeah! (+)

I created a room for my friends from school and made the room private so no random people can join it. But then I noticed other people from my school have an account so I decided to add them to the room. FB won't let me do so and idk why. What am I doing wrong?

Edit: Forgot to add in the title that this is the room you can create in Facebook messenger.
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