wp_mail() not sending messages on PHP7.3.x

[whatevs]

Hi,

I believe that this is a bug but my PHP-fu is not yet the belt color needed to further debug and fix this.
I have tested this behavior on WordPress 5.0.3 and GitHub sources from 2019-02-07, on FreeBSD and Linux Ubuntu 18.04, with PHP 7.3.1.
PHP versions 7.2 and older work as expected.

While PHP's mail() sends e-mails flawlessly, there are no attempts to open connection to a SMTP server when using wp_mail().

This issue covers all WordPress e-mails including the initial "New WordPress Site" message. Example code, working on PHP 7.2 but not on 7.3.

<?php
require('./wp-config.php');
$headers = 'From: whatevs <tester@proper-and-existing-domain.net>' . "\r\n";
wp_mail('something@proper-and-existing-domain.com','wp mail test','test test test', $headers );

The above example works with PHP 7.3 when "wp_mail" is replaced with "mail". 3rd party PHPmailer also works on PHP 7.3 with no issues.

Upon testing this behavior with tcpdump I can see that with PHP 7.2, WordPress opens a connection to 127.0.0.1:25 and tries to send the message. With PHP 7.3 there are no attempts to establish such connection on lo interface nor any other.

The following change results in: "Invalid address: (setFrom) tester@…"

--- wp-includes/pluggable.php	2019-02-08 15:37:38.459579000 +0100
+++ wp-includes/pluggable.php-debug	2019-02-08 15:37:29.683718000 +0100
@@ -364,7 +364,8 @@
 			$mail_error_data['phpmailer_exception_code'] = $e->getCode();

 			/** This filter is documented in wp-includes/pluggable.php */
-			do_action( 'wp_mail_failed', new WP_Error( 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );
+			//do_action( 'wp_mail_failed', new WP_Error( 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );
+			print('DEBUG '.$e->getMessage().' DEBUG');
 			return false;
 		}

[techsurgeons]

We're seeing this too. Haven't dug in to try and find the specific change yet.

[stefahn]

This affects the Divi contact form for example. It does not send a mail to the admin after a visitor filled out the form.

The problem is: nobody gets an error message. So the visitor thinks the message is delivered but it is not. And the admin does not see that there is something wrong (even in php_error.log I didn't see anything).

I thus changed the severity to "major".

[racosgrave]

I am experiencing a similar issue using WP 5.2.1, PHP 7.0.33-0ubuntu0.16.04.4, Easy WP SMTP Version 1.3.9.1.

BBPress notifications come out from the system fine, Test Emails from Easy WP SMTP works fine, however when I call wp_mail() from one of my scripts (has been working fine) I now get an error like 'Invalid address: (setFrom) wordpress@' when I look at WP Mail Log.

Previously I only had Content Type in the header, then did not specify any extra headers to wp_mail() which didnt work either. Only by setting the From: manually in the code (like I have redunantly in Easy WP SMTP) in the header and add that to wp_mail() does it actually work again.

[netzgestaltung]

Hi, i also do have this issue:

With PHP 7.3 on, this test script at page.php fails:

<?php

    if ( $_GET['testmail'] === "1" ) {
      ini_set( 'display_errors', 1 );
      error_reporting( E_ALL );
      
      // define the wp_mail_failed callback 
      function action_wp_mail_failed($wp_error){
        echo var_dump($wp_error);
      }
      add_action('wp_mail_failed', 'action_wp_mail_failed', 10, 1);
      
      $from = "wordpress@alphabetisierung.at";
      $recipient = "listing@majors-welt.net";
      $subject = "PHP Mail Test script";
      $body = "This is a test to check the PHP Mail functionality";
      $headers = "From: " . $from . "\r\n";
      $mail = wp_mail( $recipient, $subject, $body, $headers );
      if ( $mail ) {
        wp_die('mail sendt');
      } else {
        wp_die('mail not sendt');
      }
    }

object(WP_Error)#10509 (2) {
  ["errors"]=>
  array(1) {
    ["wp_mail_failed"]=>
    array(1) {
      [0]=>
      string(57) "Invalid address:  (setFrom) wordpress@alphabetisierung.at"
    }
  }
  ["error_data"]=>
  array(1) {
    ["wp_mail_failed"]=>
    array(6) {
      ["to"]=>
      array(1) {
        [0]=>
        string(23) "listing@majors-welt.net"
      }
      ["subject"]=>
      string(20) "PHP Mail Test script"
      ["message"]=>
      string(50) "This is a test to check the PHP Mail functionality"
      ["headers"]=>
      array(0) {
      }
      ["attachments"]=>
      array(0) {
      }
      ["phpmailer_exception_code"]=>
      int(0)
    }
  }
}

When switching the servers PHP version to 7.2-latest the email gets send

WP: 5.3–de_DE

kind regards
tom