I really apologize, but I can not use the answer in the previous argument: it does not send anything! (Not my problem I even changed the pc) I'm forced to open a new post.
Thanks a lot for the answer.
I've tested the issue in the following browsers:
Debugging the site is empty, there is nothing. I reinstalled the system in the hope of adjusting. First, it was impossible to run fopen in the log, but it is now empty by modifying the zpdata permissions. Unfortunately I can not see server errors in a free site (encrimi.altervista.org). If necessary, I can give you access credentials.