Chat is not loading

I have tutored one student for 2 semesters, so the chat history with him is quite long. All other chat rooms work properly except this particular one.I am wondering if its related to the large size of the chat history. Now the message history of us only updated to 16 Oct and I couldnt send message to this student by this app anymore. It really annoys me. I hope there is a way that can solve this problem.

Yyphil about Tutors: Homework Help & Online Tutoring