Card issuer declines may result from a rare outage within our partner’s systems or an issue with processing. Outages are not common, but if they happen, it may result in a partial (intermittent) outage or a full outage (all transactions) This will be involved in our troubleshooting process if email@example.com is contacted about card declines. The solution to this is to run the charge again once the problem has been resolved internally. You may try the charge again at a later time or contact our support team in order to get more detailed information.
If this does not apply to you, please view this general page for card declines: What If My Card Declines? – dashfi (zendesk.com)