vincent3569 on "unable to add a comment !?"

hi
in my test site (zp1.4.14), I am unable to add a comment despite comments are allowed.
I see inputs of comment form, but they are "disabled" and I can't set my name, my comment...

http://test.vincentbourganel.fr/news/photo-du-mois-fevrier-2017/

on my prod site (same server, but in another directory and with a subdomain name), I don't have the issue)

http://vincentbourganel.fr/news/photo-du-mois-fevrier-2017/

I can't figure where is the issue.
can you poiny me in the right direction ?