Short answer: Set the URL, request type and headers, then click Test API. If the response type is reported as wrong, treat the response as JSON. For a SQL database, use an external data object instead of a remote lookup.
Why it happens
- The JSON path finder only works once the field has a valid response to read, from a live test or a sample.
- POST body values come from other form fields, and only some field types can be sent.
- A remote lookup calls a web API. It can't query a database directly.
How to fix it
If the response type is reported as incorrect:
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Test the endpoint in a tool such as Postman first, so you know what it returns.
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In the field, click Test API. If you can't run a live test, click More options > Provide sample response and choose JSON.

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Click Set path to value and pick the value you need.
If a POST lookup fails:
- Check the fields you use in the Body. Use fields that hold text or number values.
- Click Test API again. Any change to the URL, headers or body needs a fresh test.
If you need data from MySQL or MSSQL:
- Set up an external data connection.
- Create an external data object and look it up from your form.
See remote lookup field overview.
Important
