Yes, the validations are on my elements. Just to try for now, I'm only using the "notempty" validation.
If I take my contact form example, here are the things I've done :
1. Creating basic fields (Name, Phone, Message)
2. Adding some validations "notempty" on the fields => not working
3. Uploading my website (from local to web)
4. Testing my form again => validations are working
5. Adding some more elements and validations => not working on these elements
6. Downloading my website back to local : the validations from step 5 are now working (???!!!)
But if I add some elements and validations again, the validations on the elements I just created (after the fresh upload/download) are not working....
Seems that I have to move my website to make the validations work, that's so weird I don't understand.