cant access my friends realm anymore

I was on my friends realms and i logged off went to log back in and the option for his realm is gone. He has tried re-adding me and it didn't work. , I've tried restarting the game and that didn't help. I didn't change my name,and he has received no error messages in sending the invention. I also have tried deleting the game and re-downloading it. I need some advice, I'm out of ideas.