Provide a link to troubleshooting docs on SMTP failure

changelog.md

@@ -33,6 +33,7 @@
 * Expose stream_context_create options via new SMTPOptions property
 * Automatic encoding switch to quoted-printable if message lines are too long
 * Add Korean translation (Thanks to @ChalkPE)
+* Provide a pointer to troubleshooting docs on SMTP connection failure
 
 ## Version 5.2.9 (Sept 25th 2014)
 * **Important: The autoloader is no longer autoloaded by the PHPMailer class**

class.phpmailer.php

@@ -2949,6 +2949,12 @@ protected function lang($key)
         }
 
         if (array_key_exists($key, $this->language)) {
+            if ($key == 'smtp_connect_failed') {
+                //Include a link to troubleshooting docs on SMTP connection failure
+                //this is by far the biggest cause of support questions
+                //but it's usually not PHPMailer's fault.
+                return $this->language[$key] . ' https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting';
+            }
             return $this->language[$key];
         } else {
             //Return the key as a fallback