OAUTH_INVALID_CLIENT

HTTP status: 400

Unknown OAuth client or unregistered redirect URI.

What it means

An OAuth authorization request named a client the server doesn't know, or a redirect_uri that isn't on the client's registered list. Per OAuth 2.1 the server must not redirect in this case, so the browser lands on this error instead of returning to the app.

Why it happens

• The MCP client's dynamic registration expired or happened against a different environment, so its client_id is unknown here.
• The client sent a redirect_uri that doesn't exactly match one it registered (only loopback URIs may vary by port).
• The connection was started from a stale or hand-edited authorization URL.

How to fix it

• Remove and re-add the Automotion connection in your MCP client so it re-registers and starts a fresh authorization request.
• If you registered the client yourself, re-register with the exact redirect_uri your app uses — matching is exact, except loopback ports.
• Retry the flow from the MCP client rather than reusing an old authorization URL.

Example

Every non-2xx response uses the same envelope; path (when present) is the exact JSON path of the offending field, and requestId identifies the request in support conversations:

{
  "error": {
    "code": "OAUTH_INVALID_CLIENT",
    "message": "Unknown OAuth client or unregistered redirect URI. Re-register the client and retry the connection from your MCP client.",
    "docsUrl": "https://useautomotion.com/docs/errors/oauth_invalid_client"
  },
  "requestId": "req_0123456789abcdef0123456789abcdef"
}

Related errors

• OAUTH_REQUEST_EXPIRED — The OAuth authorization request expired or was already used.
• UNAUTHORIZED — The request is missing a valid API key.

See the error index for the full catalog and the API overview for envelope semantics.