If the Conversation won't load because of the error "the conversation history could not be loaded," this is typically caused by an intermittent or unstable internet connection.
If you're working from home and have other devices streaming (Netflix, video games, etc.), reduce your internet usage to create more bandwidth for your computer.
If you are working from home, if possible, try to connect your computer via ethernet to a switch or router instead of over wifi.
Run a network test to ensure and confirm the stability of the internet connection.