Usually the problem is that the name you enter doesn't match with the  name on the confirmation email. Have you tried to cooy and past both the name and pass number from the confirmation email?

But, most reservations are best made elsewhere than thorough Eurail/Interrail. What route do you want to make a reservation for?

Hi, my travel agent bought the pass for me and I copy and pasted off that, but it will not work. I might contact her. 

We are travelling from Budapest to Zurich so maybe reserve through OBB?

Thanks

Yes indeed, book via tickets.oebb.at. For the night train, add the Eurail/Interrail discount and then select "One-way tickets” (NOT "Seat reservation only”).

For other trains, check here:

https://www.seat61.com/interrail-and-eurail-reservations.htm

Found out why I had an issue. It works find through the Eurail website, but not on the planner app.