Iam note sure but i heard that the RAilplanner need atleast the Android Version of 8.0 or higher :)

The Google store says that Android 6 or higher is required:

https://play.google.com/store/apps/details?id=org.eurail.railplanner

So please contact customer service:

https://eurail.zendesk.com/hc/en-001/requests/new

Hi @O.Dichtler, our Customer Support team has just replied to your email to assist you further. Cheers, 

Thanks for all advice!

In the end, it seems, I will use another device, because on mine nothing helped.

The customer service had to remove the passes from my mobile (which I had successfully added the first time running the app) in order to make it possible adding them to another device. I hope that´s a definite solution.

If not - maybe we will walk up to norway ...

Quisiera que me asesoren no puedo añadir mí pase  y tampoco el de mí marido en la aplicación Rail Planner.

Baje la aplicación y cuando agrego nombre y número de pase me aparece error o me aparece no es correcto los datos.Que hago si no puedo viajamos en 20 dias

What does the error message say?

For support get in touch with customer service via this link (write also, when you will travel):

Submit a request – Eurail Knowledge Base

Buenas noches ahora me aparece que no coinciden los datos porque será copie y pegué

Me pueden ayudar estoy hace tres días 

Puede ser que funcione mal la aplict Rail Planner

Gracias

Claudia arzivian