Hello JaneL
For which route, date and train connection? After which step does the error message appear? With which app? Could you buy other tickets for your connection? Have you also tried the SBB website? Saver Day Pass – book earlier, travel cheaper | SBB
The error message does not mean anything to us from the community, unless it is a common error.
The webshop works fine for me.
Kind regards GiuseppeL