Replying to Can't Open Message

For the past like month or so I've had a message from Guest(probably from joining a cult) but anytime I try to open it, it doesn't let me. I've tried opening it on mobile and different browsers and it doesn't load. I've been able to look at and reply to other messages but not this one. I've tried viewing my message exchange and clicking on it in the sidebar but it still wont let me read it. I don't really care about reading the message cause it's probably not important but the Message Inbox(1) thing is starting to annoy me and I wanna get rid of it.