You didn't tell where do you tried to reserve for which date and what kind of pass do you hold. 

But the reservation for Bern to Milano is 11 € per person 2nd class or 13 € per person 1st class and can be done here: https://shop.oebbtickets.at/de/ticket?cref=oebb-allgemein - this is true if you are holding a global pass and if you are resident of Switzerland having your outbound day left.

If you do hold any other kind of pass for Italy and / or if you'd need a ticket to go to Domodossola, it's not possible to do it that way.

Where are you trying to make the reservation? What type of Interrail pass do you have?

Thank you for yours answers. We hold the one-country-pass Italy. We are Swiss residents. 

The interrail reservations give me 135euros. On Trenitalia website, I can’t find reservations only, only for Trenitalia pass holders like TrenitaliaPass or other passes.

For other connections, the tickets seem to be available via OEBB, but not for this specific connection Bern 11:34 - Milan 14:40.

?

@Hektor Are you maybe based in Austria - is there geoblocking on their website? (I tried multiple days, it’s always the same)

@Hektor Are you maybe based in Austria - is there geoblocking on their website? (I tried multiple days, it’s always the same)

I am from Austria, but I never heard of this. And you did write that it works correctly for other connections, just not for the one at 11.34, so you can’t do anything wrong either. It’s also working for your specific date shown:

Are you maybe trying to do just a seat reservation? (But then it can’t be possible that other connections are shown correctly.)

@Hektor Yes, just the seat reservation. For Switzerland we have Halbtax and Juniorkarte (which OEBB doesn’t know - free rides for children in company of a parent). Is it not just the seat reservation that you tried to book for 11eur?

PS I hope you get paid for your support ;)

@Piepmatz if you only have the One-country Pass Italy, you need to buy half-fare tickets until Domodossola. It's 31.50 CHF (there are supersaver tickets somtimes, especially on the 09:34 train and you can enjoy Domo for a few hours too). The Junior card is valid of course.

And then a seat reservation between Domodossola and Milan

That seems to be the best solution. The ÖBB website will also sell reservations from Domodossola, for €10. The SBB ticket office should also be able to so that.

Unfortunately, no. But at least I did understand what's the problem is right now.

You'd like to get a reservation from Bern to Milano without the need to change places. That's not really possible to do online without a trick that is not 100 % legal. 

The cheapest and completely legal way would be to buy the interrail supplement and reservation just from Domodossola. You may have a look at Bern if these places you'd get are occupied. If they are, you'd indeed need to change places. But I don't know if this is a great problem at all. It's nothing more than changing inside your train.  

You'd need normal Juniorkarte / Halbtax tickets from Bern to Domodossola, too. 

The only not so legal turnaround to get a railpass reservation online for the whole trip is to tell the system you are holding a global pass. Then it sells an 11 € reservation for the whole trip. You need to buy tickets from Bern to Domodossola, too, as this is just a reservation and not a ticket. 

Between Bern and Domodossola you'd show just your ticket (you need to buy this using your Halbtax / Juniorkarte) and not your reservation. In Switzerland, there's no reservation required. From Domodossola, you are showing your railpass and your reservation. It's not the totally correct supplement/ reservation but it's a more expensive one and the ÖBB shop makes no difference between a one country pass and a global pass. You should know if you'd risk to do so (as I told it's not totally correct) for just not having the risk to change places. I'd opt for a reservation from Domodossola. 

Both options are available from ÖBB by selecting Interrail as discount and not choosing seat reservations but "Einzel- und Tagestickets".

@Hektor Thank you so much, this is exactly what I was looking for. I would have never found this without your help.

Just out of interest, and for future travellers, is there a way to select seats i.e. window or aisle? Anyway, thank you so much!!

@Hektor this is so helpful! I found it too late and have been in an email dispute with Eurail “Help“line for several weeks now. This is for any travellers who are also confused by the worst booking system ever:

I hold an 8 Day Italy pass. My first leg is from Zurich to Verona. I selected Seat Reservation and the train and price pops up at 91 Euros. I select it assuming that the high price is to cover the actual Swiss train fare on top of the seat reservation. On the ticket I can’t see any confirmation of the train fare. I can’t see any confirmation from Eurail booking emails either, nor on my trips page or anywhere. I search high and low for this information and Eurail always points towards The Community, where I came across this post and answer by @Hektor . I cancel my ticket and request a refund because it makes sense that it’s a systems fault. Eurail keeps 20% of the total amount. That means they pocketed 20 Euros from my fare. I have explained to them what happened and that their system and communication is confusing and not transparent. Eurail in probably the most unfriendly communication manner ever, told me it’s my fault and that I should not trust what’s written on The Community. 

I will most certainly never ever use Eurail again and currently submitting a formal complaint via the ombudsman for European Travel Companies. Anyone using this, please be aware that your rights as a Swiss consumer are not protected and Eurail couldn’t care less. 20% withheld on refunds is a sizeable amount of money and in my view, plain criminal if they don’t have a faultless system to justify it.