diff --git a/app/Http/Controllers/MailboxesController.php b/app/Http/Controllers/MailboxesController.php
index 70ed6c1c5..633fe8e1c 100755
--- a/app/Http/Controllers/MailboxesController.php
+++ b/app/Http/Controllers/MailboxesController.php
@@ -622,17 +622,22 @@ public function ajax(Request $request)
                 }
 
                 if (!$response['msg']) {
-                    $test_result = false;
+                    $test_result = [
+                        'status' => 'error'
+                    ];
 
                     try {
-                        $test_result = \App\Misc\Mail::sendTestMail($request->to, $mailbox);
+                        $test_result = \MailHelper::sendTestMail($request->to, $mailbox);
                     } catch (\Exception $e) {
-                        $response['msg'] = $e->getMessage();
+                        $test_result['msg'] = $e->getMessage();
                     }
 
-                    if (!$test_result && !$response['msg']) {
-                        $response['msg'] = __('Error occurred sending email. Please check your mail server logs for more details.');
+                    if ($test_result['status'] == 'error') {
+                        $response['msg'] = $test_result['msg']
+                            ?: __('Error occurred sending email. Please check your mail server logs for more details.');
                     }
+
+                    $response['log'] = $test_result['log'] ?? '';
                 }
 
                 if (!$response['msg']) {
diff --git a/app/Http/Controllers/SettingsController.php b/app/Http/Controllers/SettingsController.php
index 2ebcb22d2..770afb1a5 100644
--- a/app/Http/Controllers/SettingsController.php
+++ b/app/Http/Controllers/SettingsController.php
@@ -394,17 +394,22 @@ public function ajax(Request $request)
                 }
 
                 if (!$response['msg']) {
-                    $test_result = false;
+                    $test_result = [
+                        'status' => 'error'
+                    ];
 
                     try {
                         $test_result = \MailHelper::sendTestMail($request->to);
                     } catch (\Exception $e) {
-                        $response['msg'] = $e->getMessage();
+                        $test_result['msg'] = $e->getMessage();
                     }
 
-                    if (!$test_result && !$response['msg']) {
-                        $response['msg'] = __('Error occurred sending email. Please check your mail server logs for more details.');
+                    if ($test_result['status'] == 'error') {
+                        $response['msg'] = $test_result['msg']
+                            ?: __('Error occurred sending email. Please check your mail server logs for more details.');
                     }
+
+                    $response['log'] = $test_result['log'] ?? '';
                 }
 
                 if (!$response['msg']) {
diff --git a/app/Misc/Mail.php b/app/Misc/Mail.php
index 56b05a653..8b48aedd0 100644
--- a/app/Misc/Mail.php
+++ b/app/Misc/Mail.php
@@ -282,14 +282,29 @@ public static function getSystemMailDriver()
         return Option::get('mail_driver', 'mail');
     }
 
+    public static function registerSmtpLogger()
+    {
+        $logger = new \Swift_Plugins_Loggers_ArrayLogger();
+        \Mail::getSwiftMailer()->registerPlugin(new \Swift_Plugins_LoggerPlugin($logger));
+
+        return $logger;
+    }
+
     /**
      * Send test email from mailbox.
      */
     public static function sendTestMail($to, $mailbox = null)
     {
+        $result = [
+            'status' => 'success',
+            'msg' => '',
+            'log' => '',
+        ];
+
         if ($mailbox) {
             // Configure mail driver according to Mailbox settings
             \MailHelper::setMailDriver($mailbox);
+            $smtp_logger = self::registerSmtpLogger();
 
             $status_message = '';
 
@@ -302,6 +317,7 @@ public static function sendTestMail($to, $mailbox = null)
         } else {
             // System email
             \MailHelper::setSystemMailDriver();
+            $smtp_logger = self::registerSmtpLogger();
 
             $status_message = '';
 
@@ -317,15 +333,17 @@ public static function sendTestMail($to, $mailbox = null)
         if (\Mail::failures() || $status_message) {
             SendLog::log(null, null, $to, SendLog::MAIL_TYPE_TEST, SendLog::STATUS_SEND_ERROR, null, null, $status_message);
             if ($status_message) {
-                throw new \Exception($status_message, 1);
-            } else {
-                return false;
+                $result['msg'] = $status_message;
             }
+            $result['status'] = 'error';
+            $result['log'] = $smtp_logger->dump();
         } else {
             SendLog::log(null, null, $to, SendLog::MAIL_TYPE_TEST, SendLog::STATUS_ACCEPTED);
 
-            return true;
+            $result['status'] = 'success';
         }
+
+        return $result;
     }
 
     /**
diff --git a/public/css/style.css b/public/css/style.css
index 840d242b5..6af0fcdb2 100644
--- a/public/css/style.css
+++ b/public/css/style.css
@@ -4387,6 +4387,9 @@ a.disabled:focus {
     padding: 4px 6px 4px 6px;
     vertical-align: inherit;
 }
+#send_test_log {
+    max-height: 200px;
+}
 .glyphicon-spin {
     -webkit-animation: spin 1000ms infinite linear;
     animation: spin 1000ms infinite linear;
diff --git a/public/js/main.js b/public/js/main.js
index 825d20d1b..2ce244a1a 100755
--- a/public/js/main.js
+++ b/public/js/main.js
@@ -656,6 +656,7 @@ function mailboxConnectionInit(out_method_smtp)
 	    $('#send-test-trigger').click(function(event) {
 	    	var button = $(this);
 	    	button.button('loading');
+	    	$('#send_test_log').addClass('hidden');
 	    	fsAjax(
 				{
 					action: 'send_test',
@@ -668,6 +669,9 @@ function mailboxConnectionInit(out_method_smtp)
 						showFloatingAlert('success', Lang.get("messages.email_sent"));
 					} else {
 						showAjaxError(response, true);
+						if (typeof(response.log) != "undefined" && response.log) {
+							$('#send_test_log').removeClass('hidden').text(response.log);
+						}
 					}
 					button.button('reset');
 				},
@@ -786,6 +790,7 @@ function mailSettingsInit()
 		$('#send-test-trigger').click(function(event) {
 	    	var button = $(this);
 	    	button.button('loading');
+	    	$('#send_test_log').addClass('hidden');
 	    	fsAjax(
 				{
 					action: 'send_test',
@@ -797,6 +802,9 @@ function mailSettingsInit()
 						showFloatingAlert('success', Lang.get("messages.email_sent"));
 					} else {
 						showAjaxError(response);
+						if (typeof(response.log) != "undefined" && response.log) {
+							$('#send_test_log').removeClass('hidden').text(response.log);
+						}
 					}
 					button.button('reset');
 				},
diff --git a/resources/views/mailboxes/connection.blade.php b/resources/views/mailboxes/connection.blade.php
index ca17e00f9..3f60c9f93 100644
--- a/resources/views/mailboxes/connection.blade.php
+++ b/resources/views/mailboxes/connection.blade.php
@@ -130,6 +130,7 @@
                                     </span>
                                 </div>
                                 <div class="form-help">{!! __("Make sure to save settings before testing.") !!}</div>
+                                <pre class="alert alert-danger hidden" id="send_test_log"></pre>
                             </div>
                         </div>
                         <hr/>
diff --git a/resources/views/settings/emails.blade.php b/resources/views/settings/emails.blade.php
index b4b734012..86d76a7f0 100644
--- a/resources/views/settings/emails.blade.php
+++ b/resources/views/settings/emails.blade.php
@@ -104,6 +104,7 @@
                 </span>
             </div>
             <div class="form-help">{!! __("Make sure to save settings before testing.") !!}</div>
+            <pre class="alert alert-danger hidden" id="send_test_log"></pre>
         </div>
     </div>