GitHub MCP failing to start

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1

I can’t seem to get the GH MCP working. I’m signed in to GH and features like git sync work fine, but the MCP fails to start up:

2026-03-04 12:48:26.673 [info] Creating streamableHttp transport
2026-03-04 12:48:26.953 [info] Connecting to streamableHttp server
2026-03-04 12:48:27.236 [error] Client error for command Streamable HTTP error: Error POSTing to endpoint: bad request: Authorization header is badly formatted

2026-03-04 12:48:27.237 [warning] [V1] initializing -> error: Streamable HTTP error: Error POSTing to endpoint: bad request: Authorization header is badly formatted

2026-03-04 12:48:27.237 [info] Client closed for command
2026-03-04 12:48:27.237 [warning] Error connecting to streamableHttp server, falling back to SSE: Streamable HTTP error: Error POSTing to endpoint: bad request: Authorization header is badly formatted

2026-03-04 12:48:27.237 [info] Connecting to SSE server
2026-03-04 12:48:27.540 [error] Client error for command SSE error: Non-200 status code (400)
2026-03-04 12:48:27.541 [error] Error connecting to SSE server after fallback: SSE error: Non-200 status code (400) SSE error: Non-200 status code (400)
2026-03-04 12:48:27.541 [info] Client closed for command

I tried running security delete-generic-password -s “cursor-mcp” and restarting Cursor, to no avail.

1 Like
3

Same issue here.

4

Hey there.

Have you followed GitHub’s instructions for using the MCP Server with Cursor?

What does your mcp.json file look like?