Realm refusing to allow whitelist player, kicks all players

I paid for a year of my realm - I can play and one other player can play, but when my sister, Char_Smiles attempts to enter realm, the realm disconnects and closes. It kicks all other players and doesn't allow re-entry for about 10 minutes. This happens every time she attempts to enter - but she's white listed and an operator. Besides being my sister, she's also by best friend and if I can't play with her on my realm, I'll be wanting a refund pronto.