CHW-5715 PostmarkWebhookNotConfigured

postmark webhook receiver is not configured; set POSTMARK_WEBHOOK_USER and POSTMARK_WEBHOOK_PASSWORD on the server before re-enabling the webhook

Default message: postmark webhook receiver is not configured; set POSTMARK_WEBHOOK_USER and POSTMARK_WEBHOOK_PASSWORD on the server before re-enabling the webhook
HTTP status: 503 (server)

Problem. The Postmark inbound-webhook endpoint returned 503. Cause. The proxy is missing POSTMARK_WEBHOOK_SECRET (or the related signing secret), so it cannot authenticate the inbound POST. The 503 makes Postmark retry — giving the operator time to configure the secret — instead of silently accepting unauthenticated events. Fix. Set POSTMARK_WEBHOOK_SECRET (and the matching signing secret) on the proxy process and restart. HTTP 503.