If you give the exact details: date, time and route of the journey you are trying to book you will hopefully get som advice here.

Where are you trying to make the reservation?

Here are guidelines on how to make reservations.

We had multiple legs and no idea which one was giving us the error. We ended up deleting everything and going one at a time then deleting it if there wasn’t an error until we found the one causing us trouble. I think we finally have some train tickets (for times we did not prefer, but alas, all the times that show available before you spend a couple thousand dollars do not appear once you’ve spent the money) that will probably work. This whole experience was horrible. The website shows one time on the list, a different time when you click one of the trains, allows you to select one (at a bad time because the good ones are all gone) and then gives you an error which means you have to start over and delete 7+ legs and try them one at a time. It’s brutal and took us more than ten hours. This was definitely my first and last experience with Eurail. Just awful. 

You are not the only one who has struggled with the reservations at the Eurail website.

The advice from the experienced travellers in the community is to not use the Eurail website to purchase the tickets, but to purchase the tickets through the national railway companies, as described in the guidelines above. 

Eurail also has a booking fee of 2 EUR per ticket. A booking fee you can avoid at most national railway companies. 

 If you need to make any more reservations you can ask for advice on how to make those here in the community. 

The MOST common reasons for this message seem to be-and as about any newbee tends to follow the sheeppath that seems that anyone wants to:

IF in FR/SNCF: TER=local trains canNOT even be REServed

TGV have a small quota for 10€-if sold pout the price is 20 till train full-however app cannot handle the 20€ seats-as Anna already explains use other ways

The ultimate fear of anyone that trains are full monthes ahead is complete nonsense-it would make no sense to run a trainnetwork like that.

PLUS that most often its quite possible to use local trains=takes longer, more changes-to reach intended destination. This was a fine art in the past-a certain Rick Steves became famous in USA for that-but it seems this has all gone the way of infuriated dodoś

Keith, totally agree with your comments. Regretting our purchase of the global passes! Not easy and convenient at all!