Hello,
while travelling from Munich to Bologna I was asked to pay 10 euros extra for using the Brenner-Pass. I wasn't expecting this, because i used the Reservation tool and thought I had done everything correctly... Did I make a mistake there? And how can I be sure, that I have paid every necessary reservation and fee.
Thank you for your advice :)

It´s because that the Italian Part of the Journey is operated by a private company that is not part of Interrail because of that you will be charged 10€ for 2nd Class or 15€ in 1st class when traveling on the Italian Part of the connection