The advice from the experienced travellers in the community is to use other ways to make reservations than the Interrail/Eurail website. You can look at the guide in the link:

https://community.eurail.com/train-connections-reservations-47/how-to-get-reservations-105

If you, after having looked at the guide, have questions about how to make specific reservation, please give your travel details (departure date, time and route) preferably in a new post, and you will get advice. 

If you could let us know more details like Route, Date it´s easier to assist.

Anna,

for what is the Website from Interrail ? I think it is to book and plan the trip. Can you give me please a support number and not another stupid link to book seats on a big station in the EU or the usless Interrail-App. All who not yet have bought a ticket click on this link: https://www.trustpilot.com/review/interrail.eu it says all.

Ulm->Dinard

Dinard→ Nantes

Nantes → Bordeaux

Bordeaux → Ulm

I cant give you the detailed infos because with a reload of the website the basket was empty.

If done this whole process a second time on another PC but there was the same problem.

I want my money back but not only 85% !

To sell the Railpasses and get informations how to use the pass an where to go :)

Interrails main product is the Railpass
Interrail have no Contact number they only offer a online support

Sadly some Railcompanies wanna get more from the Railpassuser and because of that charge extra money from them with “Reservations”
Reservations can be booked via Interrail, by phone of the railcompany, quite often online directly on the website of the railcompany and worstcase at a ticket office.

There is no number to call and this is a community where more experienced travellers help out. 

You need to raise a request with Customer Support, preferably through this form, if you have complaints.

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

Customer Support is currently overloaded with requests so you will probably have to be patient to get an answer. 

Most bad reviews are surprisesingly just within the last weeks since the 50% Flashsale(Before that it was mixed). People write faster a bad review instead of a good review ;) 

The problem is that Eurail the Company behind the Railpass never expected such a huge demand on the 50% Flashsale of the passes.
Another Reason
Many buyers just saw the 50% discount, and the deadline as it was just offered for about 5days . That they didn´t checked before if the pass is that what they need and how the system works. Interrail.eu have quite a lot informations about the railpass. Most travelers wanna go south (because it´s warm there). The Railcompanis in the South (France,Italy,Spain) know it and thought they could get more money out of the Railpassuser by letting them pay for “Reservations”. Interrail.eu provides the informations that some trains need a reservation.
Most trains doesn´t need a reservation but ofcourse the most popular ones need one. Many buyers feel cheated as they didn´t read carefully the informations and blame now Eurail/Interrail for that.

The Railpass is not perfect and still have it´s errors but in general it a great offer if you know how to make the best out of it you can save a lot of money.

And if somebody asks
Till yet i just used by myself one Interrailpass back in 2019 (As iam eligable for a different offer) but worked in the last 8 years with thes Railpass offers in Europe (Eurail,Interrail,Britrail,European EastPass, BalkanFlexipass,GermanRailpass).
Pass 2 & 3 are bought during the Flashsale and will be used this summer and next spring.