I've had problems in Canada. When you use a card there it automatically gets a stop put on it by the card issuer (as apparently there is a lot of card fraud out of Canada)
Aware of this from our previous visit, this year we notified our credit card company (Egg) before we went that yes, we are in fact going to Canada.
They said basically "Thanks for letting us know. It will be noted on your file, but for fraud prevention reasons the card will be automatically stopped when you try and use it there and you'll have to call up to confirm."
Apparently you can't "confirm" in advance, even if you know the exact dates you'll be there 🙄