Intermittent NMI payment rejections for one merchant

Update timeline

1. resolved Nov 11, 2026, 05:25 PM UTC

   November 11, 2026. All times are PST. 9:25 a.m. — First observed rejection. NMI returned a surcharge error on some payments for one merchant when no surcharge was requested. Other payments for the merchant continued to process. 10:42 a.m. — Investigating. Customer Service escalated the payment rejections. Around 11:00 a.m. — Identified a mitigation. OpenPath could send an explicit zero-value surcharge when no surcharge was requested. We found no OpenPath release or relevant configuration change at the onset. We reached out to NMI to verify whether its handling changed. 11:45 a.m. — Monitoring. We verified a production hotfix that omits the surcharge field when the value is zero. 12:02 p.m. — Resolved. We verified the first approved debit payment after the hotfix. By 1:09 p.m., 11 zero-surcharge debit payments had been approved and we had observed no recurrence of the surcharge error. We are continuing to work with NMI to confirm the underlying cause.

2. postmortem Nov 11, 2026, 09:11 PM UTC

   On November 11, 2026, NMI rejected some payments for one merchant with an error stating that a surcharge could not be applied to the card type. Our review found 55 rejected attempts across 18 orders between 9:25 and 10:49 a.m. PST. All 55 attempts had a recorded surcharge of $0.00. Other payments for the merchant continued to process. We apologize for the disruption to customers completing their purchases. Our review found no OpenPath release or relevant merchant, routing, or connector configuration change when the errors began. OpenPath’s existing integration could include an explicit zero-value surcharge in requests to NMI. We reached out to NMI to verify what it received and whether its validation or merchant settings changed. The trigger remains unconfirmed. We validated a hotfix in staging and deployed it to production. It omits the surcharge field when the value is zero and preserves nonzero surcharge values. The same release improved redacted logging for incoming requests so support can see which fields checkout sent. Production verification passed at 11:45 a.m. PST, and we verified an approved sale at 11:49 a.m. The first approved debit payment after the hotfix was at 12:02 p.m. PST. By 1:09 p.m. PST, 11 debit payments with a $0.00 surcharge had been approved, with no repeat surcharge errors observed. We’ll continue monitoring and review NMI’s findings when we receive them.