Sending emails does not work

When someone registers on my site it does not send out the registration email – hence, no one can register.

I have installed the WP-Mail-SMTP plugin and enabled it, and have it set to “Use the PHP mail() function to send emails.” – and then, when I told it to send a test email to me, it said it was successful; however I never get the email.

NOTE: My spam filter is switched off.

I also tried it with “Send all WordPress emails via SMTP.”, and that gave the following error..

Test Message Sent

The result was:

bool(false)
The full debugging output is shown below:

object(PHPMailer)#135 (45) {
  ["Priority"]=>
  int(3)
  ["CharSet"]=>
  string(5) "UTF-8"
  ["ContentType"]=>
  string(10) "text/plain"
  ["Encoding"]=>
  string(4) "8bit"
  ["ErrorInfo"]=>
  string(43) "SMTP Error: Could not connect to SMTP host."
  ["From"]=>
  string(19) "[email protected]"
  ["FromName"]=>
  string(25) "Timothy Hall (Fred's son)"
  ["Sender"]=>
  string(0) ""
  ["Subject"]=>
  string(46) "WP Mail SMTP: Test mail to [email protected]"
  ["Body"]=>
  string(68) "This is a test email generated by the WP Mail SMTP WordPress plugin."
  ["AltBody"]=>
  string(0) ""
  ["WordWrap"]=>
  int(0)
  ["Mailer"]=>
  string(4) "smtp"
  ["Sendmail"]=>
  string(18) "/usr/sbin/sendmail"
  ["PluginDir"]=>
  string(0) ""
  ["Version"]=>
  string(5) "2.0.4"
  ["ConfirmReadingTo"]=>
  string(0) ""
  ["Hostname"]=>
  string(0) ""
  ["MessageID"]=>
  string(0) ""
  ["Host"]=>
  string(20) "mail.swing-thing.com"
  ["Port"]=>
  string(2) "25"
  ["Helo"]=>
  string(0) ""
  ["SMTPSecure"]=>
  string(0) ""
  ["SMTPAuth"]=>
  bool(true)
  ["Username"]=>
  string(19) "[email protected]"
  ["Password"]=>
  string(8) "free4air"
  ["Timeout"]=>
  int(10)
  ["SMTPDebug"]=>
  int(2)
  ["SMTPKeepAlive"]=>
  bool(false)
  ["SingleTo"]=>
  bool(false)
  ["smtp"]=>
  object(SMTP)#136 (7) {
    ["SMTP_PORT"]=>
    int(25)
    ["CRLF"]=>
    string(2) "
"
    ["do_debug"]=>
    int(2)
    ["do_verp"]=>
    bool(false)
    ["smtp_conn"]=>
    bool(false)
    ["error"]=>
    array(3) {
      ["error"]=>
      string(27) "Failed to connect to server"
      ["errno"]=>
      int(0)
      ["errstr"]=>
      string(58) "php_network_getaddresses: getaddrinfo failed: System error"
    }
    ["helo_rply"]=>
    NULL
  }
  ["to"]=>
  array(1) {
    [0]=>
    array(2) {
      [0]=>
      string(19) "[email protected]"
      [1]=>
      string(0) ""
    }
  }
  ["cc"]=>
  array(0) {
  }
  ["bcc"]=>
  array(0) {
  }
  ["ReplyTo"]=>
  array(0) {
  }
  ["attachment"]=>
  array(0) {
  }
  ["CustomHeader"]=>
  array(0) {
  }
  ["message_type"]=>
  string(5) "plain"
  ["boundary"]=>
  array(2) {
    [1]=>
    string(35) "b1_c99db40d7a65448a8195956642b37f07"
    [2]=>
    string(35) "b2_c99db40d7a65448a8195956642b37f07"
  }
  ["language"]=>
  array(13) {
    ["mailer_not_supported"]=>
    string(25) " mailer is not supported."
    ["provide_address"]=>
    string(55) "You must provide at least one  mailer is not supported."
    ["execute"]=>
    string(19) "Could not execute: "
    ["instantiate"]=>
    string(36) "Could not instantiate mail function."
    ["authenticate"]=>
    string(35) "SMTP Error: Could not authenticate."
    ["from_failed"]=>
    string(35) "The following From address failed: "
    ["data_not_accepted"]=>
    string(30) "SMTP Error: Data not accepted."
    ["recipients_failed"]=>
    string(56) "SMTP Error: The following SMTP Error: Data not accepted."
    ["connect_host"]=>
    string(43) "SMTP Error: Could not connect to SMTP host."
    ["file_access"]=>
    string(23) "Could not access file: "
    ["file_open"]=>
    string(33) "File Error: Could not open file: "
    ["encoding"]=>
    string(18) "Unknown encoding: "
    ["signing"]=>
    string(15) "Signing Error: "
  }
  ["error_count"]=>
  int(1)
  ["LE"]=>
  string(1) "
"
  ["sign_cert_file"]=>
  string(0) ""
  ["sign_key_file"]=>
  string(0) ""
  ["sign_key_pass"]=>
  string(0) ""
}
The SMTP debugging output is shown below:

SMTP -> ERROR: Failed to connect to server: php_network_getaddresses: getaddrinfo failed: System error (0)

My SMTP settings have been double checked and are correct, along with the appropriate username and password.

I am stumped.

Please, anyone – what am I doing wrong here?

Thanks.