HTTP 400 · type invalid_request_error · retryable false

defaultMessage Template variables do not match the approved template.

invalid_variables

Template body or header variables do not match the approved template schema.

What to do

1. Fetch the template via GET /v1/templates (or dashboard) and match positional {{1}}, {{2}}, … counts.
2. Send all required body variables as strings; empty strings are usually invalid.
3. For media headers, provide a public HTTPS URL that matches the header component type.
4. Do not invent extra variables beyond the template definition.
5. Fix the request body and retry with a new Idempotency-Key if the previous accept never created a message.