PHP mail()函数返回true但不返回消息

这是我的问题，

我有一个简单的PHP脚本发送电子邮件到本地主机与水银邮件服务器和阅读它与Mozilla雷鸟。这是工作。

然后，我将XAMPP版本升级到1.8.1，我的函数返回true，但没有发送电子邮件。

<?php
$to = "root@localhost.com";
$subject = "Hi!";
$body="test";
$headers = "From: root@localhost.com"; 
if (mail($to, $subject, $body, $headers)) {
    echo "Message successfully sent!";
} else {
    echo "Message delivery failed...";
}
?>

我试着用雷鸟发送电子邮件到root@localhost.com，它成功了。

我试着把php。ini中的邮件功能改成这个，但不行

    [mail function]
    ; XAMPP: Comment out this if you want to work with an SMTP Server like Mercury
     SMTP = localhost
     smtp_port = 25
    ; For Win32 only.
    ; http://php.net/sendmail-from
    sendmail_from = root@localhost.com
    ; XAMPP IMPORTANT NOTE (1): If XAMPP is installed in a base directory with spaces (e.g. c:'program filesC:'xampp) fakemail and mailtodisk do not work correctly.
    ; XAMPP IMPORTANT NOTE (2): In this case please copy the sendmail or mailtodisk folder in your root folder (e.g. C:'sendmail) and use this for sendmail_path.  
    ; XAMPP: Comment out this if you want to work with fakemail for forwarding to your mailbox (sendmail.exe in the sendmail folder)
    sendmail_path = "'"C:'xampp'sendmail'sendmail.exe'" -t"
    ; XAMPP: Comment out this if you want to work with mailToDisk, It writes all mails in the C:'xampp'mailoutput folder
    sendmail_path = "C:'xampp'mailtodisk'mailtodisk.exe"
    ; Force the addition of the specified parameters to be passed as extra parameters
    ; to the sendmail binary. These parameters will always replace the value of
    ; the 5th parameter to mail(), even in safe mode.
    ;mail.force_extra_parameters =
    ; Add X-PHP-Originating-Script: that will include uid of the script followed by the filename
    mail.add_x_header = Off
    ; Log all mail() calls including the full path of the script, line #, to address and headers
    ;mail.log = "C:'xampp'php'logs'php_mail.log"
I try to change sendmail.ini to this but not work
; configuration for fake sendmail
; if this file doesn't exist, sendmail.exe will look for the settings in
; the registry, under HKLM'Software'Sendmail
[sendmail]
; you must change mail.mydomain.com to your smtp server,
; or to IIS's "pickup" directory.  (generally C:'Inetpub'mailroot'Pickup)
; emails delivered via IIS's pickup directory cause sendmail to
; run quicker, but you won't get error messages back to the calling
; application.
smtp_server=localhost
; smtp port (normally 25)
smtp_port=25
; SMTPS (SSL) support
;   auto = use SSL for port 465, otherwise try to use TLS
;   ssl  = alway use SSL
;   tls  = always use TLS
;   none = never try to use SSL
smtp_ssl=auto
; the default domain for this server will be read from the registry
; this will be appended to email addresses when one isn't provided
; if you want to override the value in the registry, uncomment and modify
;default_domain=mydomain.com
; log smtp errors to error.log (defaults to same directory as sendmail.exe)
; uncomment to enable logging
error_logfile=error.log
; create debug log as debug.log (defaults to same directory as sendmail.exe)
; uncomment to enable debugging
;debug_logfile=debug.log
; if your smtp server requires authentication, modify the following two lines
auth_username=
auth_password=
; if your smtp server uses pop3 before smtp authentication, modify the 
; following three lines.  do not enable unless it is required.
pop3_server=
pop3_username=
pop3_password=
; force the sender to always be the following email address
; this will only affect the "MAIL FROM" command, it won't modify 
; the "From: " header of the message content
force_sender=
; force the sender to always be the following email address
; this will only affect the "RCTP TO" command, it won't modify 
; the "To: " header of the message content
force_recipient=
; sendmail will use your hostname and your default_domain in the ehlo/helo
; smtp greeting.  you can manually set the ehlo/helo name if required
hostname=

任何想法?