91 | Issuer unavailable
This code indicates the transaction could not be completed because the issuer was unavailable to process the authorization request.
What This Code Means
Response code 91 (“Issuer unavailable”) is used when the issuer could not be reached or could not respond to the authorization request within the required timeframe. This is a system availability outcome, not a funds or permission decision. It indicates that the authorization process did not complete due to issuer-side unavailability or response failure. The code does not indicate whether the card would have been approved if the issuer were available. It also does not imply the card is invalid or restricted; it reflects a temporary processing availability problem.
Where Users Usually See This Code
- Payment gateway declines during issuer outages
- Card-present declines when authorization cannot be completed
- Processor reports showing response code 91
Why This Code Appears
- Issuer systems were temporarily unavailable
- Network routing to the issuer failed or timed out
- Authorization response was not received within required limits
- Issuer-side maintenance or transient disruption affected availability
What Typically Happens Next
- Authorization is declined or marked as not completed
- Merchant or processor records the decline as issuer unavailable
- Subsequent attempts may succeed once issuer availability returns
What This Code Is Not
- It is not insufficient funds (see 51)
- It is not a restriction-based decline (see 62)
- It is not a transaction parameter validation error (see 12/13/14)
Troubleshooting Checklist
- □ Check whether declines correlate to a specific time window or region
- □ Review processor logs for timeout or routing indicators
- □ Document the incident pattern for reconciliation and reporting
- □ Follow official acquirer/processor status channels for outage confirmation
Notes And Edge Cases
Issuer availability issues can be short-lived and may affect only certain transaction channels or regions. Some processors retry routing automatically, while others return the code quickly based on timeout thresholds. During widespread network incidents, 91 can increase across many issuers simultaneously. The code does not differentiate between issuer downtime and certain network routing failures; it communicates that issuer response was not obtained.