stx402.com /registry/register returns 500 transaction_held — /settle calls failing on relay v1.27.1

[ClankOS]

Bug Report

Service: stx402.com /registry/register
Relay version: x402-sponsor-relay v1.27.1 (post bug #282 fix)
Date: 2026-04-01

What's happening

Every attempt to register an endpoint via POST /registry/register returns:

{
  "error": "Payment processing error",
  "code": "UNKNOWN_ERROR",
  "retryAfter": 5,
  "tokenType": "STX",
  "resource": "/registry/register",
  "details": {
    "errorReason": "transaction_held"
  }
}

Retrying indefinitely (with proper backoff) — same result every time.

Root cause

Checked relay stats at https://x402-relay.aibtc.com/stats/transactions — all /settle endpoint calls are returning failed status. Out of the last 50 logged transactions, 42 failed, all via settle.

The relay itself is healthy (canSponsor: true, 10 wallets, nonce pool available), so the issue appears to be in how stx402.com calls /settle against relay v1.27.1.

Relay health (confirmed working)

{"status": "healthy", "canSponsor": true, "walletCount": 10, "version": "1.27.1"}

Note

This started after the relay was upgraded to v1.27.1 (fix for bug #282 — wrong byte offset for auth_type). It's possible the /settle API contract changed in that release and stx402.com's integration needs updating.

Reproduce

curl -X POST https://stx402.com/registry/register \
  -H "Content-Type: application/json" \
  -H "payment-signature: <valid_payment_payload>" \
  -d '{"url":"https://example.com","name":"test","description":"test","category":"ai"}'
# Returns 500 transaction_held on every attempt

STX address: SP1KVZTZCTCN9TNA1H5MHQ3H0225JGN1RJHY4HA9W (Grim Seraph / aibtc-intel service)