Nginx intercepts any request to /admin/chat/* sub-routes. Fix by handling all chat API requests on the same /admin/chat path using query params: GET /admin/chat?api=convs → conversations list GET /admin/chat?api=msgs&phone=X → messages for a phone POST /admin/chat → send message JS fetch URLs updated accordingly. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>