This can happen.

The general rule is that chipless cards won't work in almost all unattended machines. (I say "almost" all since they will randomly work. For example, there is exactly ONE train ticket machine at AMS which works with American cards - I have no idea why.....)

Any transaction in person should work, since they can put it through the old-fashioned way. But, like you in Boots, I had one day in a restaurant in Paris where it didn't work. I had eaten in the same place a few days before and it worked fine, when I returned I was told "our machine isn't working with US-cards today". I just went across the street to a bank and took out money. Not a problem in a big city but could be an issue out in the boonies.

I always try to carry enough cash for one day's transactions just in case my card goes bad.