chat-ui/docs/source/configuration/common-issues.md

Common Issues

403: You don't have access to this conversation

This usually happens when running Chat UI over HTTP without proper cookie configuration.

Recommended: Set up a reverse proxy (NGINX, Caddy) to handle HTTPS.

Alternative: If you must run over HTTP, set the following env var:

COOKIE_SECURE=false

This automatically sets COOKIE_SAMESITE to lax, which is the correct value for HTTP deployments.

Also ensure PUBLIC_ORIGIN matches your actual URL:

PUBLIC_ORIGIN=http://localhost:5173

Models not loading

If models aren't appearing in the UI:

1. Verify OPENAI_BASE_URL is correct and accessible
2. Check that OPENAI_API_KEY is valid
3. Ensure the endpoint returns models at ${OPENAI_BASE_URL}/models

Database connection errors

For development, you can skip MongoDB entirely - Chat UI will use an embedded database.

For production, verify:

• MONGODB_URL is a valid connection string
• Your IP is whitelisted (for MongoDB Atlas)
• The database user has read/write permissions