Problem with Reservation TGV to Paris

Hello, I hope you can help me.

I booked the Interrail Global-Pass, because I wanna travel from Augsburg (DE) to Angouleme (FR) on the 2nd of November.

My preferred choice would be the train from “Augsburg” 07:16 - 12:31 to “Paris Est” and then from “Paris Montparnasse” at 14:19 - 16:35 to “Angouleme”. The return is supposed to be on the 4th of November.

Now the problem is that I can't buy a reservation on the Interrail website for the TGV to Paris because this error message appears:

"Prices unavailable.
No price results were found. Pass holder reservations may be sold out for this connection, but there are other ways to check for available seats—more info below our timetable." 

At first I thought that simply this particular trip was fully booked, but even the furthest in the future TGV train (10/12/22) to Paris has this error message (I even tried different parameters, like starting point, date, time, etc.).
I have also not been able to find any other website through which I could book only the reservation for the train to Paris on the 2nd of November.

Any advice is appreciated.