There is a bug in php running on windows.
The problem is the format in the header tags. The solution is to set the sender in the php.ini just before running the mail() function.
ini_set(‘sendmail_from’, ‘[email protected]’);
past it in line 252 in the wp-contact-form-7.php file (version 1.9.2)
The mail will still send with the information specified in the plugin settings.
Hope this will help. It did for me.
