A couple of years ago I was unable to make some online purchases with my debt card.
It was always vendor specific and there didn't seem to be any logic to it. I talked to my bank, and they talked to MasterCard, and I would speak with vendors technical support or billing. Nothing out of the ordinary.
This was happening for over a year and I got by with using a credit card as needed (which I don't like to use in general).
Anyway, the common denominator was all these vendors used Stripe for payments. I email Stripe and eventually someone noted that my card number had been flagged by some algorithm in the past and had been blacklisted. For background, to my current knowledge, I've never had an issue with identity-theft, had others fraudulent charge my account, or done anything out of the ordinary.
That fact that this happens, and you have no notification or no clear recourse is frustrating. To be clear, I do not think this is specific to Stripe - I think all large services are vulnerable to this.