Which website did you try to book tickets on?

In any case, DO NOT use the Interrail or SNCF website for possible connections. Use OEBB, SBB.

There seems to be a problem, maybe with the connection to the SNCF system:

By the way, I hope you did notice my remark in the previous discussion that the TGV station is not located in the city and that there are reservation-free alternatives to the "Aix-en-Provence” station that is in the city.

I have tried via the website of NMBS and Interrail, but it does not work for several dates.

In any case, you have an included alternative, with the TER trains, included with your pass.

Again/repeat: check out the RES free local TER trains-that bring you into the town itself and not some sugarbeet park&ride stop without sometimes even connect bus.

There is a continuous ´problem´ with RES con the many FR TGV (and the apparent insistence led out by all these planners to stubborn or unknowing rail-newbees): MOST (in fact not all, or one could say the quota = 0) TGV trains offer only a very few pass-holder seats for 10€. IF this quotum is fully taken (and it may be that booking 4 persons means f.e. that 2 could be in and 2 out) then SNCF is said to offer 20€ seats as long as there are any spare seats. NOW this EU/IR-app has been many times mentioned as not being able to handle THESE 20€ places.

I really do not quite understand that immense fear of those newbees for REServ 2 month ahead. MOst likely as a tipical tourist you stay the odd day in Nice or aorund (Cannes? Monte Carlo anyone?) then go to a SNCF counter, show pass and ask for them to do it. Chances the 10€ seats are gone are close to 100% then-but apparently already now and chances to find the 20€ seats are like 99,99%

Chances that the always very unhappy jolly FRench SNCF workers lay on yet another strike are in fact higher as finding cheap seats