What does the VARTA error `invalid_request` mean?
HTTP status: 400 · Type: invalid_request_error
What it means
The request body or a parameter is malformed, or missing something the endpoint requires.
What causes it
Raised directly by handlers across the API — for example a POST /v1/calls body that isn't a JSON object, or is missing agent_id or to (backend/app/api/v1/calls.py), a non-object context, or a POST /v1/trunks request missing address (backend/app/api/v1/telephony.py). It is also the fallback code for any unrecognised 400 the platform returns.
What to do
Check the response's param field — it names the offending field — and compare your request body against the endpoint's documented shape.