[edubs25]

Credit card networks can vary regionally even under the same brand names (like MC/Visa). They are not ubiquitous. Depending on the network the merchant is using, they may or may not be able to connect to your specific card's issuer.

I'm from the US and I've had my chip based Visa pin debit card declined in France due to network incompatibility that neither side could figure out (at a McDonalds of all places) - the authorization just wasn't making it to the issuer.

Basically the further you get from you issuing bank's region/network, the more likely you are to run into problems, regardless of what country you're in. In the US because payment processing industry is so big, merchants are more likely to accept more networks than in other countries because they're paying more to support it or have negotiated better rates with middle men like FDC or directly with Visa/MC.

I think in Germany most MC is actually run using the Maestro network and merchants get hit with either per transaction fees or high interchange rates for using non-maestro cards (if they even opt-in for that with their acquirer).