While abroad 2 bank cards suddenly have stopped working. They worked yesterday, in the same country

There are several possible causes for the cards not working:

• The card issuers refused the transactions. This can be due to a multitude of factors:

  • Transactions abroad triggered security blocks. Note that such blocks may not happen on the first transaction abroad or in a given country, they may happen after a specific type of transaction (e.g. ATM withdrawal vs. purchase, using chip+pin or using the magnetic strip), certain specific merchants or types of merchants, a number of transaction, a given amount (per transaction or total in that country), and so on. Trying to second-guess the security rules of a card issuer is a game you will lose, they sometimes defy any apparent logic.

  • Note that security blocks may be general for the card or may be limited to specific merchants or types of merchants or types of transactions.

  • You exceeded transaction thresholds abroad. Most card issues have limits on how much you can spend in a day and/or week and/or month, and there may be separate limits for domestic and international transactions, as well as separate limits for withdrawals and purchases, etc.

  • Related to the above, you may have large authorisations pending on your card(s). For instance if you are staying at a hotel and are in "post-pay" mode (settle at the end of your stay), the hotel will usually take a hold for the total cost of the stay + incidentals. Even if it's not (yet) an actual debit, it is counted against both your balance and your spend limits.

  • If you use cards a lot, especially in "card not present" mode (purchases on web sites), banks will often block cards after a number of transactions, or a cumulated amount. This is unrelated to being abroad or not (though it may be compounded by that). I had cards on which I had lots and lots of transactions, and every few weeks they would get blocked until I called them, even though the merchants were always the same.

  • The card issuer had a technical issue which prevented them from accepting card payments. This is rare, but it does happen.

  • Note that the two cards being blocked at the same time may be just a coincidence, or they may be the result of the two card issuers being actually the same bank trading under different names, or one the issuers actually using the services/infrastructure of the other. This is especially common for all the new "online banks" which rely a lot on the infrastructure of either their "parent" bank, or another unrelated established bank, or a third party service provider.

• Or it was an issue somewhere between the merchant and the card issuers:

  • It could be a fault in the national network in your home country (in many countries, things go merchant -> national network -> Visa or Mastercard -> national network -> issuer). This would have affected payments for all (or most) cards issued by banks in that country.

  • It could be a fault somewhere in the complex connections between the country you were in and your issuers' country.

• There's also the case that you used a type of card not supported by the merchant

  • This is becoming quite rare nowadays with Visa and Mastercard-branded cards, but there must still be some merchants/countries here and there who only accept one or the other. Of course, if we are talking about Amex, JCB, Diner's Club, Discovery or Union Pay, this is a common issue.

  • Some cards require an authorisation, and can't ever be used "offline", but only with terminals connected to the network so that the issuer can actually confirm the charge. Others can be charged without an authorisation (the merchant takes a risk but they may be willing to accept it), and some cards also allow charges without an authorisation up to a certain amount (per transaction or cumulated over several transactions).

We definitely do not have enough information to ascertain what the actual reason could have been. The first thing I would do is to contact the issuer banks. They will usually (though not always) be able to see if the request actually reached them or not, and what the reason was for the decline if it did reach the server. Do not count on there being any useful information available in your online banking. Some banks will post information there in some circumstances, others won't.

Some of the possible reasons (mostly technical issues, or incompatibility with a specific merchant) will resolve themselves: just try the card again a few hours later or at a different merchant. Others will lead to the card remaining blocked until you contact them.