Friends cannot find Realm server Invitations

Hello!

 

I'm trying to invite friends to a realm I recently started, but or whatever reason, they're unable to find the invitation. They have tried re-sizing the window and turning off fullscreen, and I have tried multiple times to uninvite and reinvite them to no avail. Please get back to me with a solution as soon as possible. 

 

Thanks!

 

Zack