Weird glitch

I cannot see my friend's messages and they are not muted. I don't know what to do. I also can only join their world once, and then it starts saying "Unable to connect to world" the rest of the time I want to join. The worlds are not a realm. My sister can see my friend's messages and can join when she wants, but I can't. Gamertag: Bleaklow

my friend's gamertag: endermoth9569