Successful response

The Idempotency-Key header is not 1 to 255 printable ASCII characters

Missing, malformed or wrong client credentials (every case the same)

The app is disabled, or the change was sent from a web page (Origin, or a Sec-Fetch-Site other than none)

No such delivery of this app

Only a failed delivery can be retried

Some of the input is not valid, or a query parameter this request does not take was sent; fields names each

Rate limited (60 calls a minute per app; a test delivery 10 an hour); see Retry-After

Temporarily unavailable; safe to retry