Issuer Unavailable and Acquirer Error are payment refusal codes.
It means that payment can’t be confirmed by acquirering bank / credit card issuer (bank which gave out the credit card).
Some reason for it could be:
- Bank is down for maintenance
- Bank does not recognize the card, card is blocked/blacklisted, etc
- Bank has temporarily technical problem
- Some other technical reason in "background" communication which we can’t control
- Any other reason
So, it might be that after day or week same card will just work but it does not have to be the case.
Advice for end user:
- Contact the bank and ask is card listed/valid/blocked and what could be the reason that it’s not accepted for online payments
- Try another card
- Try another payment method