What kind of issues? It could be some sort of communication problems, rather than rejections by your bank. Or, maybe, a local bank rejecting your card for their own reasons (I don't really know how this works).

I was visiting Philippines recently, and wasn't able to withdraw cash - the ATMs (I've tried different banks' ones) were rejecting me with a generic error message. So I've contacted my bank to check what's wrong and if they're blocking me for any reason. Turned out that they haven't seen any transaction attempts at all - like something along the path wasn't working (no clue, really). The suggested method of trying an ATM in a different part of the city worked.

I've also had issues with some payments via PoS terminals. Normally, when payment fails I get a push notification about the failure - but none happened at those times. So, I guess, this could be similar.