AxiosError: Request failed with status code 401 (Notion MCP not sending the Authorization header)

AxiosError: Request failed with status code 401 (Notion MCP not sending the Authorization header)

TL;DR: Verify the token works with a direct curl to the Notion API first; that isolates the server as the culprit. Make sure the server version you run actually reads the token env var; older builds dropped the header. Upgrade the server and confirm the env var name matches the README.

The error

Error in http client [AxiosError]: Request failed with status code 401

Fix it

1. curl the Notion API's who-am-I endpoint with your token and Notion-Version header.

Expected: It returns 200, proving the token.

1. Check the token env var name in your MCP config against the server README.

Expected: You find a mismatch or an old server version.

1. Upgrade @notionhq/notion-mcp-server to the latest and set the token under the documented name.

Expected: The config matches the README.

1. Restart the client and retry.

Expected: Calls succeed; the header is now attached.

When this applies

The Notion token works via curl but the MCP server's own requests go out without the Authorization header and 401.

When this does NOT apply

If curl also 401s, the token is the problem. If headers are misquoted in Docker, see the n8n headers skill.

Tool compatibility

makenotion/notion-mcp-server, older versions

Also seen as

• notion MCP missing authorization header
• AxiosError 401 notion-mcp-server
• notion MCP server not passing token

Why it happens

A bug in some server builds failed to read the token env var into the HTTP client, so requests left without Authorization. The token was valid; the server just never sent it.

Edge cases

• Debug logs showing the outgoing request confirm the missing header.
• Wrapper scripts that inject headers are a workaround, not a fix.
• Pin the working version in your config after upgrading.