Milan to Lyon - Difficulty booking inter-country train reservation

First of all, congratulations on succeeding where most Americans fail: booking tickets on the Trenitalia site. The site routinely rejects US credit cards so you must have a magic one!

In this particular case, I think your problem is that going from Milan to Lyon requires at least one connection outside of Italy and I expect that it is impossible to book tickets on the Trenitalia site for legs that don't either start or end in Italy.

There is one direct train which leaves Milan at 16:10 and arrives at Lyon-St Exupery at 21:24. Did you try booking that one?

If you want to take the 06:40 train with a connection in Chambery, I think you will need to book Milan-Chambery on the Trenitalia site and Chambery Lyon Part Dieu on tgv-europe.com. To keep the site in English and to avoid being bumped to the Rail Europe site, choose Great Britain as your country of residence.

If you want to take the 08:25 train with a connection in Geneva, book Millan-Geneva on the Trenitalia site and Geneva-Lyon Part Dieu on the Swiss Rail site.

Thanks Tim for the tip!! Yes, I've been attempting the 16:10 departure time. I've tried changing different variables and I finally got my answer!! It appears that for inter-country reservations, you can only book one person at a time. So now, I have my four tickets in the cart but of course my magic card fails me and like a slot machine, I keep trying till my credit card is accepted!