Judge reason

The only 2xx came from Postmark's literal test token, not the account credential. evidence/04-send-with-documented-test-token.json records POST https://api.postmarkapp.com/email with X-Postmark-Server-Token=POSTMARK_API_TEST -> HTTP 200 {"ErrorCode":0,"Message":"Test job accepted","MessageID":"fb0ca0df-..."}; postmarkapp.com/auth.md (fetched at transcript line 8) states that token 'exercise[s] the sending endpoints without delivering anything... no mail leaves Postmark', i.e. a provider-side sandbox, so it does not prove an authenticated send of the core operation. The real send with the operator credential is evidence/03-send-with-operator-token.json: HTTP 401 {"ErrorCode":10,"Message":"Request does not contain a valid Server token."}. The same credential returned 401 on GET /server, /message-streams, /messages/outbound (02-server-scoped-discovery.json) and on /sendersignatures, /domains, /servers with the Account-token header (01-sender-discovery.json), plus Bearer and curl variants (transcript 120, 165, 199); its shape was 46 chars, not a Postmark UUID token (transcript 72). Sender discovery therefore never succeeded and From was the docs example sender@example.com, accepted only because the test token skips sender verification. Code (send_email.py), saved request bodies and printed stdout do match each other and nothing was mocked locally; recipient test@blackhole.postmarkapp.com is Postmark's documented black-hole address and transport was the HTTPS API, not SMTP or dashboard.

Attempt record

1. 1:05Answered from saved key: Postmark API keyno wait
2. 6:13Blocked by a prerequisiteThe Postmark Server API token supplied through the benchmark input mechanism is invalid: every live endpoint returned 401 ErrorCode 10, which postmarkapp.com/auth.md documents as terminal ('the credential is wrong... only a human can rotate or reissue'), and the attempt's 5 input requests were exhausted.