What day/train/country/connection?

This issue is fairly often reported and almost always its the result of a REServ that is NOT possible to do online-too early, train full (very, very rare), INTernational (not possible), quota sold out (FRance) and quite a lot of these are all warned for in the general info re REServ. but noone seems to read first and has to hit head before grasping.

Agree that a proper waring/explanation in these cases would have been more helpful-and save time for us too