Errors and troubleshooting

MCP transport failures may appear as HTTP errors, JSON-RPC errors or a successful tool response with isError: true.

Common errors

Signal	Meaning	What to do
HTTP `401`	Missing or invalid authentication	Reconnect OAuth or replace the static key
HTTP `429`	Credential, organization or daily rate limit reached	Slow down and retry later
JSON-RPC `-32600`	Invalid JSON-RPC request	Send a valid `2.0` request envelope
JSON-RPC `-32601`	Unsupported method	Use `initialize`, tools or resources methods
JSON-RPC `-32602`	Arguments do not match the live schema	Call `tools/list` and correct the arguments
JSON-RPC `-32002`	Insufficient WhatWins AI data credits	Reduce the request or wait for renewal
`isError: true`	The selected tool failed during execution	Read the returned message, then retry once

The connector does not appear

Confirm the URL is exactly https://whatwins.io/api/mcp.
Leave OAuth Client ID and Secret empty.
Make sure custom connectors or apps are enabled by the AI workspace admin.
Remove the incomplete connector and add it again.
Start a new conversation after reconnecting.

Claude says WhatWins is unavailable

Open Settings → Connectors, find WhatWins and confirm it is connected and enabled. In Claude Code, run:

claude mcp list

Then open /mcp inside Claude Code to inspect connection status.

ChatGPT cannot find the tools

Confirm Developer mode is enabled, the custom app finished scanning tools and the app is allowed in the current workspace. Enterprise and Edu workspaces may require an administrator to approve or publish the app.

A tool rejects valid-looking arguments

The server schema is authoritative and may evolve. Call tools/list, inspect the schema returned for that tool and retry with only supported fields. Do not guess enum values.

Empty is not always an error

A successful response with zero rows means no verified result matched the current scope and filters. Widen the date range or relax filters before retrying.