On the wire
Ships with HTTP status 413, carrying "code": "RU-4012" in the response body alongside the human-readable error message. Existing fields are never replaced by the code: it is additive.
Common causes
- Comments far beyond the dialog's own character limit, from a hand-rolled client.
- A name or email far longer than a real one.
How to fix it
- Use the official SDK's dialog, which enforces the same limits client-side.
- Keep comments under 4000 characters, name under 200, email under 254.
Still stuck?
Ask support and mention RU-4012: the code pins down the exact refusal path, so you skip the diagnostic back-and-forth.