ISO 8583 response code: 05

"Do not honour" is the catch-all decline. The issuer's authorisation system evaluated the transaction and said no, and the response carries no diagnostic beyond that. It covers risk-scoring declines, internal account states the issuer will not describe, and rules that fire for reasons the issuer considers its own business. Because it absorbs so many distinct situations, a 05 tells you almost nothing about whether a retry could ever succeed — which is exactly why it frustrates integrators, and why chasing its "real" cause from the merchant side usually fails.

• The issuer's fraud or risk model scored the transaction badly — an unfamiliar merchant, country, amount or device.
• An account restriction the issuer will not disclose: a block on ecommerce or international use, a card not yet activated, a suspected-compromise hold.
• Missing or implausible data the issuer treats as a soft risk signal — no AVS result, no CVV result, an unusual merchant category code for that cardholder.
• The real reason is one of the specific codes, such as insufficient funds or an expired card, but the issuer has chosen to generalise it to 05.

1. Ask the cardholder to contact their issuer. This is not a deflection — the issuer is the only party that knows the reason, and it will tell the cardholder things it will not tell you.
2. Offer another payment method rather than retrying. An immediate identical retry almost always returns 05 again, and counts against the card's velocity limits.
3. If 05 is spiking across many cards at once, stop looking at the cards. Check whether your merchant configuration, currency, merchant category code or 3-D Secure setup changed — a merchant-level change shows up as a wall of generic declines.
4. Send the strongest data you can on the next attempt: 3-D Secure authentication, AVS and CVV where supported. Thin data makes a marginal transaction score worse.

• ISO 8583 00Approved or completed successfully
• ISO 8583 01Refer to card issuer
• ISO 8583 51Not sufficient funds
• ISO 8583 62Restricted card
• Stripe do_not_honordo_not_honor

• ISO 8583 message parser
• Card test toolkit

What is the actual reason behind a do-not-honour decline?

There is no way to find out from the merchant side, and that is by design. The issuer chose a code that withholds the reason — commonly because disclosing it would help someone testing stolen cards work out which cards are live. The cardholder can call their issuer and be told; you cannot.

Is a 05 worth retrying?

Rarely, and never immediately or unchanged. Some issuers will approve a later attempt if the underlying condition was temporary, but most will not, and repeated attempts against one card look like card testing and can get the card blocked outright. If you retry at all, retry once after a meaningful delay, and prefer asking for a different card.

Why did every card start returning 05 at once?

That pattern is almost never about the cards. A sudden wall of generic declines usually follows a change on your side or your acquirer's — a new merchant category code, a currency you are not boarded for, 3-D Secure switched off, or a migration to a new acquiring endpoint. Compare a failing message against one from before the change and look for what differs.