Why did I get charged an international service fee?

I'm curious, could you please explain to me why I was charged an international service fee for my recent cryptocurrency transaction? I've made similar transactions in the past without incurring such a fee, so I'm a bit puzzled about this charge. Could it be related to the specific cryptocurrency I was trading, the exchange platform I used, or some other factor? I'd appreciate it if you could provide some clarity on this matter.