diff --git a/mail/inc/class.mail_integration.inc.php b/mail/inc/class.mail_integration.inc.php
index c843fda877..7ffa57acc5 100644
--- a/mail/inc/class.mail_integration.inc.php
+++ b/mail/inc/class.mail_integration.inc.php
@@ -246,7 +246,7 @@ class mail_integration {
 		$data_message = preg_replace_callback(
 			'/[-_+=~\.]{'.self::MAX_LINE_CHARS.',}/m',
 			function($matches) {
-				return substr($matches[0],0,self::MAX_LINE_CHARS);
+				return substr($matches[0],0,  mail_integration::MAX_LINE_CHARS);
 			},
 			$mailcontent['message']
 		);