Hi llllFenixllll and welcome to the NS Community! 
Unfortunately, we have a malfunction at the moment which makes it impossible to add your OV-chipcard. We are working on this, so please try this again later this week.

Hi Lorena, another question, I have the flex subscription in this new personal chip card (the one that is 5.10 euros per month). Then, I was trying to add the bicycle lending service from the app to the card. However, in the checkout step it says that I can not add that service because I have the flex monthly subscription. Does this means that I have to order yet another card only for the bike renting?

Thanks! :)

OV-fiets is already included with NS Flex , so no need to have a separate OV-fiets subscription.