Discover Payment Decline Code
Discover Decline Code 91: Authorization System or Issuer System Inoperative
Category Issuer or Network AvailabilityRetry Guidance Soft Decline (Editorial Classification)By Payment Defender Editorial TeamUpdated July 17, 2026Last reviewed July 17, 2026
What Discover Decline Code 91 Means
Discover decline code 91 (Authorization System or Issuer System Inoperative) indicates that the authorization or issuer system was inoperative when the request was sent.
Where the Response May Come From
Code 91 means the issuer's authorization system was temporarily inoperative and could not respond. It is a transient issuer-availability condition, so a later attempt and the processor response are the reference.
Common Reasons for This Response
Common causes include issuer or authorization system downtime or maintenance.
Should the Merchant Retry the Payment?
A retry after a short delay often succeeds once the issuer system is back online; rapid repeated retries during the outage rarely help.
Recommended Merchant Action
Wait a short time and retry, and if code 91 continues, advise the customer to try again later or use another card.
What to Tell the Customer
Let the customer know the bank's system was temporarily unavailable and ask them to try again shortly.
How to Reduce Similar Payment Failures
Tracking code 91 by issuer helps identify which banks are experiencing outages so you can time retries and set customer expectations.
Important Limitations
Decline-code meanings vary by processor, gateway, and payment environment, and issuers do not always disclose the specific reason behind a response. The retry classification on this page is Payment Defender editorial guidance, not an official network rule. Merchants should confirm handling with their processor or gateway.
Related Decline Codes
Sources and Review Information
Last reviewed July 17, 2026
Raw network-response codes are supplemental to the complete processor or gateway response. Meanings and recommended actions can vary by issuer, processor, gateway, card network, payment method, region, and merchant configuration.