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401 unauthorized on simple-auth example #731
Description
Describe the bug
Unable to get access to MCP server
To Reproduce
Followed all instructions in https://github.com/modelcontextprotocol/python-sdk/tree/main/examples/servers/simple-auth
Expected behavior
Using mcp-inspector, gotten 401 error when connecting via http://localhost:8000/sse
SSE transport: url=http://localhost:8000/sse, headers=Accept
Received 401 Unauthorized from MCP server: SSE error: Non-200 status code (401)
Please let me know if any information is needed
Reacted by Shintaro Yamasaki
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ihrpr commentedon May 17, 2025
@luarss please can you share server logs?
luarss commentedon May 19, 2025
Hi @ihrpr, logs as follows.
Here is my oauth app config
MCP inspector config
luarss commentedon May 19, 2025
Hi @ihrpr found the regression lies actually in mcp-inspector client, not the code.
Code example works with
npx @modelcontextprotocol/inspector@0.11.0. Perhaps we could add that blurb while they fix the issue?modelcontextprotocol/inspector#390
ihrpr commentedon May 19, 2025
Thank you, looking into it!
bttopfer commentedon May 20, 2025
I ran into the same issue - using inspector@0.11.0 does not help. Using /mcp - so streamable http transport.
Authentication works fine when I run with custom test script (initialize, initialized.....), but fails with 401 in inspector and I do not even get to my implementation of OAuthAuthorizationServerProvider ( no logs for e.g. load_access_token). If I disable auth it works fine.
zackify commentedon May 20, 2025
Yeah it’s really really annoying they don’t release the new update.
But you can work around it like I have.
Use v11 and select SSE. Then hit connect.
Oauth.
Now once oauth is successful. You start v12 and switch to streamable http because only v12 sends the header there 😆😆
Or everyone is just using provider specific cloudflare tooling right now.
felixweinberger commentedon Oct 3, 2025
Closing as an inspector issue.