Requesting help creating new Pass Cover Number

Me and three friends have been planning a train trip through Europe in July. Our country of origin is Sweden and we all have our Interrail mobile passes ready. We have now gotten around to booking seats on some of the trains, but have struggled to book high speed trains from Amsterdam to France on July 6th. The seats seem to be fully sold out on the Interrail website, leaving us the option of instead booking via travel.b-europe.com. However, one member of our group didn’t receive the same confirmation email as the rest of us - his is lacking the Pass Cover number that is required for booking seats via external non-Interrail websites. We are positive that he bought an Interrail pass and not a Eurail pass. He is the only one of us with this issue and he has not been able to reach Interrail customer support.

Here’s the info about the specific trains I’m trying to book:

Amsterdam Centraal (13:15) - Paris Nord (16:38)

Paris Gare de Lyon (17:37) - Marseille-St-Charles (20:57)

both on date: 06/7 - 2022

They don’t seem to be sold out on b-europe.com, so the only thing stopping me from making the reservations is that I need my friend’s passcover number!

@Magdalena you seem to have been able to help people in the past with this issue, is there any chance you could help us as well? We would greatly appreciate any guidance, however small!

Best regards, Edvin