Solution to SMTP Error: Could not connect to SMTP host when phpmailer sends email

When I was working on a project before, I made a function to send emails using phpmailer, "CI Framework Combined with PHPmailer to Send Emails". It was launched yesterday (I just started using Sina Cloud, but it was too expensive, so I switched to Alibaba). When testing, I accidentally reported an error when sending an email...

I wiped it, and it worked fine when I was not online. It succeeded every time. At first I thought it was There was a problem with the smtp address (I used 163 mailbox) and later changed it to QQ mailbox. I found that it still didn't work. I had no choice but to ask Du Niang. Later, after looking at the answers on Baidu, I realized that in addition to Google's smtp server receiving the request "smtp" will be accepted. Other servers are like the 163 I use. QQ and other servers must receive uppercase "smtp" requests... emmmmm....

Then in class.phpmailer.php I put

1 public function IsSMTP() {
2     $this->Mailer = 'smtp';
3   }
4 
5 //改成
6 public function IsSMTP() {
7     $this->Mailer = 'SMTP';
8   }

and then:

 1 switch($this->Mailer) { 
 2         case 'sendmail': 
 3           return $this->SendmailSend($header, $body); 
 4         case 'smtp': 
 5           return $this->SmtpSend($header, $body); 
 6         default: 
 7           return $this->MailSend($header, $body); 
 8       } 
 9 
 10 
 11 //改成
 12 switch($this->Mailer) {
 13         case 'sendmail':
 14           return $this->SendmailSend($header, $body);
 15         case 'SMTP':
 16           return $this->SmtpSend($header, $body);
 17         default:
 18           return $this->MailSend($header, $body);
 19       }

I originally thought this would be enough. I restarted Apache and tested it again. As a result, the first error was solved, and another error appeared:

Could not instantiate mail function

? ? ? ? ?

I don’t know if you guys showed up. I had bad luck, so I had to ask Du Niang for help, and finally found the reason: some virtual hosts or servers blocked the "fsockopen() function" for security reasons, resulting in the inability to send emails. .

The following is the solution:

First, remove the following two semicolons in php.ini

;extension=php_sockets.dll

;extension=php_openssl.dll

I had already removed it when I used PHPmailer before, here is just a reminder.

Then replace the fsockopen function

Replace the fsockopen function in the class.smtp.php file with the pfsockopen function:

 1 $this->smtp_conn = @fsockopen($host,    // the host of the server 
 2                                                    $port,    // the port to use 
 3                                  $errno,   // error number if any 
 4                                  $errstr,  // error message if any 
 5                                  $tval);   // give up after ? secs 
 6  
 7  
 8 //fsockopen改为： 
 9 $this->smtp_conn = @pfsockopen($host,    // the host of the server
 10                                  $port,    // the port to use
 11                                  $errno,   // error number if any
 12                                  $errstr,  // error message if any
 13                                  $tval);   // give up after ? secs

After setting this up, I can successfully send emails. If you also have this problem, you can try it by referring to the above example.

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