One of my chats appears to be locked and won't let me submit new messages. Did I hit a hard limit for messages in a single chat?

One of my chats appears to be locked and won’t let me submit new messages. Did I hit a hard limit for messages in a single chat?

I’m using this chat to develop a long, continuous story. I’m stuck now and can’t submit new messages. I’m using ChatGPT 4o PLUS. Other chats work fine.

Usually when you hit the limit, messages you send would start disappearing alongside responses. Not sure if that’s what you are currently having a problem with but if it is, then you’ve probably hit the maximum length of this chat. The only way to continue would be to start a new chat.