You can't book with the app but it should work on the website : laptop or Iphone

Hi, thank you for your reply. I tried different browsers, Safari and Google Chrome with my iPhone for many times, but it always says “something went wrong” after I filled my card information for the payment. And it worked with no problem on my computer using the same credit card.

That's weird. Maybe someone else can help ? Post screenshots of the error message

Do you think that the website requires its desktop side instead of its mobile site to complete the reservation?

I've seen more complaints about reservations on the website not working on a phone browser, while they do work on a laptop. I don't have an explanation for it.

There are often other (and cheaper) ways to book reservations though than via Eurail. See this thread:

and this page:

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

If you tell which train you want to book (route, date, departure time), then people can help.

Thank you very much for your helpful advice. I try to book tickets using other websites!