Laravel 5.1 - Some pages are not found on production serveur - "Page you are looking for could not be found"

I have a problem with some "routes" in my old Laravel 5.1.46 project.

When I try to access to some routes, like admin/exercices/creer or admin/exercices/1928, I have this: "Sorry, the page you are looking for could not be found.". I can access to thoses pages when I work on the test or local serveur. But not on the production serveur. Other routes like admin/missions/creer are working properly.

I tried php artisan route:list to compare the routes on each serveur: it's the same everywhere. I also tried php artisan route:cache and php artisan route:clear. Nothing changed.

I can remember we changed the routes path (for example: "admin/modules/creer" became "admin/exercices/creer"). I think we did it manually, directly in the routes.php file. But it waas a long time ago and since then, it already worked properly. So I don't think it comes from that, but Idk.

I'm also not good at sysadmin, so maybe it's more about the config of the server than code and laravel... In this case, any idea here does it come from? I have no clue, and I might need help.

Thanks a lot for reading! And let me know if you have even a tiny idea!

via Chebli Mohamed