I think I figured out what causes you to no longer be able to gain classes. If you go to the fortuneteller and retrain to change your class too many times? You just lose the ability to unlock classes on your other classes or something like that? IT's very confusing, it works sometimes and sometimes it doesn't work.On my new game I created a new character, got them to priest level 10, they unlocked their classes like normal, then went to the fortuneteller, retrained them to ranger and then retrained them to solider, then re-equipped the ranger class to them and grinded to level 10 without unlocking any classes. Im not sure if this is exactly what causes, there's no way for me to tell without knowing what levels classes are supposed to unlock, and it also takes a long time to test stuff because I have to roll new characters and then grind levels. I did create MORE new characxters and didn't retrain them at all, and ranger unlocked Samurai at 7 and Tech ranger at 9.