> For the complete documentation index, see [llms.txt](https://doc.thordata.com/doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.thordata.com/doc/scraping/serp-api/mcp-server/troubleshooting.md).

# Troubleshooting

Troubleshoot Thordata MCP Server connection, authentication, engine selection, rate limits, empty results, and tool call errors.

**"missing user token" / "missing bearer token"**

Please provide your authentication token via the URL path <kbd>/{YOUR\_API\_TOKEN}/mcp</kbd>, Authorization: <kbd>Bearer YOUR\_API\_TOKEN</kbd>, or X-Thor-Serp-Token: <kbd>YOUR\_API\_TOKEN</kbd>.

**"unknown engine"**

Please first invoke the `list_engines` tool to view the list of available engines, or consult the `thor://engines` resource to retrieve the engine schema.

**"Rate limit exceeded"**

Please wait or upgrade your Thordata plan.

**"No Results"**

Please try a different query or switch search engines.