I have "generously supported" the Holy See through smart investment of my Papal influence, all cardinals now respond to every single whim and desire of mine, and there's a fellow Catholic nation or two that keep getting on my toes that I'd like to punish by excommunicating them.
However, I couldn't find a single nation that I could excommunicate, apparently they all have "good relations with the Pope". How does one have bad relations with the Pope? Does it have something to do with the Papal State? Or the prestige of the target nation? Or am I missing something else here? What are the conditions that allow excommunication?