diff --git a/modules/advanced_mailer/advanced_mailer.admin.controller.php b/modules/advanced_mailer/advanced_mailer.admin.controller.php
index ef6fea4f4..397a3da87 100644
--- a/modules/advanced_mailer/advanced_mailer.admin.controller.php
+++ b/modules/advanced_mailer/advanced_mailer.admin.controller.php
@@ -229,6 +229,11 @@ class Advanced_MailerAdminController extends Advanced_Mailer
 		$recipient_name = $recipient_config->recipient_name;
 		$recipient_email = $recipient_config->recipient_email;
 
+		if (!config('mail.default_from'))
+		{
+			$this->add('test_result', 'Error: ' . Context::getLang('msg_advanced_mailer_default_from_email_not_set'));
+			return;
+		}
 		if (!$recipient_name)
 		{
 			$this->add('test_result', 'Error: ' . Context::getLang('msg_advanced_mailer_recipient_name_is_empty'));
diff --git a/modules/advanced_mailer/advanced_mailer.controller.php b/modules/advanced_mailer/advanced_mailer.controller.php
index 6140760c0..904822dcd 100644
--- a/modules/advanced_mailer/advanced_mailer.controller.php
+++ b/modules/advanced_mailer/advanced_mailer.controller.php
@@ -32,7 +32,10 @@ class Advanced_MailerController extends Advanced_Mailer
 		if (!$mail->getFrom())
 		{
 			list($default_from, $default_name) = $this->getDefaultEmailIdentity();
-			$mail->setFrom($default_from, $default_name);
+			if ($default_from)
+			{
+				$mail->setFrom($default_from, $default_name);
+			}
 			$default_reply_to = config('mail.default_reply_to');
 			if ($default_reply_to && !$mail->message->getReplyTo())
 			{
@@ -51,10 +54,13 @@ class Advanced_MailerController extends Advanced_Mailer
 				$original_sender_email = $sender ? array_first_key($sender) : null;
 				$original_sender_name = $sender ? array_first($sender) : null;
 				list($default_from, $default_name) = $this->getDefaultEmailIdentity();
-				if ($original_sender_email !== $default_from)
+				if ($original_sender_email !== $default_from && $default_from)
 				{
 					$mail->setFrom($default_from, $original_sender_name ?: $default_name);
-					$mail->setReplyTo($original_sender_email);
+					if ($original_sender_email)
+					{
+						$mail->setReplyTo($original_sender_email);
+					}
 				}
 			}
 		}
@@ -132,7 +138,7 @@ class Advanced_MailerController extends Advanced_Mailer
 		if (!$email)
 		{
 			$member_config = getModel('module')->getModuleConfig('member');
-			$email = $member_config->webmaster_email;
+			$email = strval($member_config->webmaster_email);
 			$name = $member_config->webmaster_name ?: 'webmaster';
 		}
 
diff --git a/modules/advanced_mailer/lang/en.php b/modules/advanced_mailer/lang/en.php
index f4f4be412..ad0c195b1 100644
--- a/modules/advanced_mailer/lang/en.php
+++ b/modules/advanced_mailer/lang/en.php
@@ -107,6 +107,7 @@ $lang->msg_advanced_mailer_sender_name_is_empty = 'Please enter the sender\'s na
 $lang->msg_advanced_mailer_sender_email_is_empty = 'Please enter the sender\'s email address.';
 $lang->msg_advanced_mailer_sender_email_is_invalid = 'The sender\'s email address is invalid.';
 $lang->msg_advanced_mailer_reply_to_is_invalid = 'The Reply-To email address is invalid.';
+$lang->msg_advanced_mailer_default_from_email_not_set = 'The default sender email address is not configured.';
 $lang->msg_advanced_mailer_recipient_name_is_empty = 'Please enter the recipient\'s name.';
 $lang->msg_advanced_mailer_recipient_email_is_empty = 'Please enter the recipient\'s email address.';
 $lang->msg_advanced_mailer_recipient_email_is_invalid = 'The recipient\'s email address is invalid.';
diff --git a/modules/advanced_mailer/lang/ko.php b/modules/advanced_mailer/lang/ko.php
index 3dd173fcd..a177fc86d 100644
--- a/modules/advanced_mailer/lang/ko.php
+++ b/modules/advanced_mailer/lang/ko.php
@@ -107,6 +107,7 @@ $lang->msg_advanced_mailer_sender_name_is_empty = '보낸이 이름을 입력해
 $lang->msg_advanced_mailer_sender_email_is_empty = '보낸이 메일 주소를 입력해 주십시오.';
 $lang->msg_advanced_mailer_sender_email_is_invalid = '보낸이 메일 주소가 올바른 메일 주소가 아닙니다.';
 $lang->msg_advanced_mailer_reply_to_is_invalid = 'Reply-To 메일 주소가 올바른 메일 주소가 아닙니다.';
+$lang->msg_advanced_mailer_default_from_email_not_set = '기본 발신자 이름과 주소가 설정되어 있지 않습니다.';
 $lang->msg_advanced_mailer_recipient_name_is_empty = '받는이 이름을 입력해 주십시오.';
 $lang->msg_advanced_mailer_recipient_email_is_empty = '받는이 메일 주소를 입력해 주십시오.';
 $lang->msg_advanced_mailer_recipient_email_is_invalid = '받는이 메일 주소가 올바른 메일 주소가 아닙니다.';