Errors

submission_unavailable

503 – Mail submission unavailable. The mail server did not take the message.

Mail submission unavailable. Answered with 503.

What it means

The mail server did not take the message. Nothing was sent.

What to do

Retry after a few seconds with the same request; this is transient.

The body

{
  "type": "https://tigby.eu/problems/submission_unavailable",
  "title": "Mail submission unavailable",
  "status": 503,
  "detail": "…what was refused, naming this request's own values",
  "code": "submission_unavailable",
  "doc_url": "https://docs.tigby.eu/errors/submission_unavailable",
  "agent_hint": "…the next step, for software"
}

Branch on code. The detail names this request's own Handle, id or limit and is not part of the contract.