I couldn't use a 6 digit pin in Italy. Some ATMs in London,UK didn't like it either. Singapore it's mandatory for a 6 digit pin so have no idea if a 4 digit pi

I couldn't use a 6 digit pin in Italy. Some ATMs in London,UK didn't like it either. Singapore it's mandatory for a 6 digit pin so have no idea if a 4 digit pin will work, anybody been there?