dentro il php.ini cerca la riga:
codice:
; For Unix only.  You may supply arguments as well (default: "sendmail -t -i").
;sendmail_path =
sendmail_path = /path/to/exim -t

Andrew W
28-Apr-2005 12:19
I spent weeks trying to work out why PHP couldnt send mail through Exim (called locally) when for all other purposes Exim worked fine. Here, after hours of work is the answer and I hope it saves someone else some time:

PHP by default calls sendmail/exim/whatever with the options -t & -i

-i is causing Exim to sit there waiting for more input, not detecting the end of the message. You need to tell it not to use -i by manually specifying the arguments you DO want on sendmail_path like this:
http://it.php.net/mail