Cardholders in Denmark are reporting problems with using the new Visa/Dankort chip card to pay for purchases made abroad.
Denmark's Payment Business Services (PBS) says cardholders have mainly had problems at high street and airport shops in England, as well as a number of Web sites.
PBS says the "long lifetime" of the new Visa/Dankort cards may be causing the problems.
Visa International is currently investigating the situation.