Can't connect: 401 / Authorization header

"Can't connect" is 90% a 401. Here's how to dissect.

Slima Authorized Apps: when connection fails, this page confirms token presence and status

401 — Unauthorized

Most common. The server received the request but didn't see / didn't accept the Authorization header.

Diagnose step 1: confirm the token exists

Local stdio:

npx slima-mcp@0 status

Should say "Token valid for [email protected]".

If "No token found" → re-run:

npx slima-mcp@0 auth

See: Get SLIMA_API_TOKEN

Diagnose step 2: token not expired / revoked

Account → Authorized apps — check:

Token is listed
Not flagged "expired" or "revoked"

If it is → re-auth.

Diagnose step 3: client config is right

Restart Claude Desktop and inspect logs:

macOS:

tail -f ~/Library/Logs/Claude/mcp*.log

Windows:

type "%APPDATA%\Claude\Logs\mcp*.log"

Look for:

MCP server slima exited unexpectedly → command misconfigured
Failed to fetch ... → network issue
Authorization header not set → token not read

Other connection errors

`403 Forbidden`

Token valid but wrong permissions — token belongs to a deleted account or has wrong scope.

Fix: re-auth.

`408 / Timeout`

Network slow or middleware blocking. Fix: try different network / proxy / VPN.

`5xx`

Slima server issue. Fix: wait 5–10 min and retry / check status.slima.ai.

WWW-Authenticate flow

Web OAuth clients (claude.ai / ChatGPT) on 401 get WWW-Authenticate: Bearer realm="slima", scope="..." — the client should auto-trigger OAuth reauth.

If reauth doesn't trigger → bug in the client's MCP implementation. Try restarting / removing and re-adding the connector.