Hey, heads up! If you are using Joomla! you should know that Joomla! uses 2 different separated sessions and login system for frontend and backend.
The frontend and backend applications are completely unrelated in Joomla! and thus the login sessions for users.
This means that when you are logged in into Joomla! backend you are not logged in also in the frontend side. The chat application works entirely in the frontend and thus rely on the frontend Joomla! session.
For this reason you always need to login into Joomla! frontend to be a valid users also for the chat application.