It means that your pass doesn't cover that journey. Multiple options :

- low-cost companies which don't accept Interrail/Eurail passes : Flixtrain, Ouigo, .italo, Iryo

- mountain railways in Switzerland such as Interlaken - Lauterbrunnen, Grindelwald and above. For those you usually get a 25-50% discount

If you want precise advice, let us know the route

Also possible: the app is wrong.

But we can't tell without exact information (route, date, departure time).

Help! All the morning journeys from Antwerp central to Frankfurt main are saying “not in pass network”! And the other says “seat reservation required”! How could that be? Suggestions? 

The planner is incorrectly giving a connection Antwerp - Brussels using Eurostar.

Search separately and use the reservation free NS IC service for this leg.

Both operators, Eurostar and DB between Brussels and Germany are reservation compulsory, DB is only compulsory for the summer.

The app likely shows you the Eurostar services as they’re the fastest between Antwerp and Brussels: you cannot use these for domestic travel. Split the search and you’ll find at least 6 trains an hour between both cities. With a quick look departures at xx:05, xx:06, xx:19, xx:25, xx:39, xx:54 (some are faster than others!).

The Brussels - Cologne - Frankfurt ICE has required reservations in summer due to frequent overcrowding.

For further questions mention travel date.

Hi! Thank you SO much for helping! It’s nearly midnight here and I must leave tomorrow morning July 3rd! Was hoping for a train around 8:00am or 9! 

Then pick your train from Brussels Midi and book a reservation. The DB ICE at 08.23 and 10.25 are direct to Frankfurt and cheaper than the Eurostar at 09.25 which would require a change at Cologne.

Book the reservation for the ICE at www.bahn.com  or on the DB app.

Book Eurostar at www.raileurope.com on the desktop site only.

Then take any train from Antwerp (except Eurostar) that gives you a good margin to catch your connection in Brussels

Ok! Thank you so much. I will hope to take thr 7:25am train to Brussels and then the 8:32am train to Frankfurt. Is there a reason not to book seat reservations on the eurail planner app? 

Definitely do not wait to book the 08:32 ICE from Brussels-Nord. There are less than 10 seats left.

The Eurail website (you can’t book anything on the app) is confusing, unreliable and most importantly charges extra... It would be 8€ for this route through Eurail while 5.20€ through DB or 3€ through OBB.

Oh gosh thanks. Will go and try and do now! First time so hope it works. We are 5!!! Many many thanks!

You won’t be seated together but at least you should all be onboard…

Let me know if you need alternatives (mention the destination).

Oh no. I just tried to book the 5 of us. It’s me and 4 of my kids and it said fully booked…. Any ideas of any other way for me to get on a morning train to Frankfurt that will get me there by 11:30am starting here in Antwerp. Somewhere else nearby I can go from Antwerp to catch a morning train to Frankfurt?  The 10:30am train gets me in too late…. 

Hmmm. I went back to try again and now it looks like for 15 euro it will reserve me and my kids. Does that make sense? 

Try through the ÖBB website: using the seat reservation only option. DB sometimes struggles with mandatory reservations, even for their own trains.

There are 7 seats left in carriage 22 so it should assign you there (although not next to each other). Let me know!

EDIT: 15€ is the correct price. Book that.

Do you have something important in Frankfurt at 11:30? You can't guarantee that the ICE will arrive on time. Delays could happen.

I can’t thank you enough for helping me! I just went through the whole payment process and after trying to process my card and all I got the message that the reservation wasn’t possible!

I don’t have a meeting but a full days itinerary for our one day in Frankfurt! We move on to our next destination on Thursday…

Just tried again. Took my cc information et al and then after processing gave me the same message. Any ideas please? 
 

Guess it is full now (or was already but the map didn't update).

I'd follow plan A and speak to staff on the platform at Brussels-North. They are likely to let you hop on as they're generally understandable. You'll likely stand but perhaps you could share a free seat and switch from time to time.

If they forbid you entry follow this route:

- IC Bruxelles-Nord - Liège-Guillemins 09:07 - 09:59

- RE Liège-Guillemins - Aachen Hbf 10:19 - 11:22

- RE Aachen Hbf - Köln Hbf (Cologne) 11:51 - 12:44

- ICE Köln Hbf - Frankfurt (Main) Hbf -> any service, they run frequently (and are often late)

(Or you directly follow plan B and leave Antwerp at 06:25, 07:25, etc. -> they all run at least hourly.)

Good luck!

Good night. I'm sure you'll find something.

Even if you arrive after midday in Frankfurt (likely) you'll have enough time to walk around the city. No need to rush and be stressed all along.

Hmmm. 4 kids that will be tired! As will their mom at the rate I’m going here! It’s after 2:00am! so plan a  won’t work unfortunately. Is there any shorter route you can think of without changing so many trains? We have a lot of luggage and so on and off trains is a bit of a doozy… and we already have to take a train from Antwerp somewhere…. Any and all additional thoughts are so appreciated. And I am so grateful for above option you gave me. Thank you so so much! 

Well sorry to say but you should've planned earlier if changes are an issue/travel time is an issue, etc.

The route with Liège and Aachen is the second best (over the ICE from Brussels). I don't think I can do better.

It's weird as I still see more than 4 seats available on the 08:32. Perhaps if they're split too far the system refuses to book... idk.

@thibcabe 
thank you so much for your help! We made it! By the skin of our teeth with delayed trains et al!  Many many many thanks for taking the time to help!