Issues with reserving seats for trains in Italy in July - No Results

Hello,

I am planning a family vacation in July 2024. I purchased 5 Day 1 Month Global Pass for me and my family.  I was able to reserve seats for us to go from London to Paris but when I go into Seat Reservations and attempt to reserve seats from Milan Italy to Florence and other trips from one Italian city to another for middle of July (still within the 1 month timeframe of my first planned train ride from London to Paris), I get an error message “We can't find any trains that match your search. Please change your search and try again.”  I have tried multiple cities, times, stations, and I continue to get the error when going through Seat Reservations.  I know trains are running because I can go onto other sites and see them available.  I am willing to pay for the seat reservations.  Am I doing something wrong? Am I able to purchase seat reservations before my passes are activated for July (I was able to with London to Paris)?  Is there an issue getting seats reserved for cities in Italy for July?  Am I booking too early?