Hi all, thanks for letting me know. It has been flagged with the relevant team and they are working on it at the moment. I will update you once its solved. 

Update: the Pass Cover number generator is working again.

@mcadv I fixed it by calling B-rail, but still would be nice if the number would work for future travelers :) 

Please write an error report to Customer Support through this form.

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

Is this new? Never heard about it-or rather read.

Perhaps NMBS is itself not yet on the current with the new nrs? They do seem to check if a cover nr has in fact been released from stock.

@noa-je kan NMBS (=b-ral als je dat niet wist) bellen zoner dat nr-dat schellt ook 4€ kosten voor online maar kost wel een hoop aan belkosten.

Afh van welke rit (waarom niet ietsepietsie verder gedacht en meer info gegeven?) evt ook SNCF bellen.

Calling NS is cheaper, since NMBS’s phone number is rather expensive :/

And since NMBS charge 4€ per online booking (only online!), I only use their website to check availability.