Good evening Yorgo M and welcome at the NS Community!

How unfortunate that you are unable to order a subscription. According to your message, I think that your personal details at your Mijn NS account are incomplete. I want to advise you to contact our Customer Service so they can help you further.

A screenshot of the exact error could help to determine the cause. But indeed, I'd check personal details.:

• The address must be in the Netherlands or otherwise the website can't handle it.
• A phone number (doesn't need to be real, it just needs to have 10 digits) can also help.
• Check that your date of birth is there.

I too had a fair bit of trouble while signing up for an NS Flex subscription because (the value of my) date of birth was somehow “Invalid date”. I wouldn't even let me enter/change the field, nor did the red error message even alert me that the date of birth was the problem. I never typed the wrong date of birth, or my date of birth at all, which led me to believe it must've been getting my date of birth from my Mijn NS account. I added it there and rhen it worked.

Groetjes,

Jos