This panel talks to an agent CLI running on your own machine. The browser cannot start it, so it has to be running before this connects.
If you already have the desktop tools kit, open a terminal in that folder and run:
node tools/td-chat.mjs --serve
Don't have that folder? It is a separate, optional download from the extension itself: vespryx.com/portal, under "Desktop tools", has the download and the setup steps.
Either way, it needs an ACP agent installed, and it never sees a model key: it drives the agent you already pay for.
td-chat.mjs is running fine. Only one chat panel can hold its socket at a time, and another one (another tab, or another copy of this panel) just took it. This panel will not reconnect on its own.