diff --git a/inc/mail.php b/inc/mail.php
index 9994ac63e3abd0ff3d66c7cd8feb80e6a54bf307..9f1b1f3d633d5047acbfb0f98310127422b346e7 100644
--- a/inc/mail.php
+++ b/inc/mail.php
@@ -27,7 +27,7 @@ if(!defined('MAILHEADER_EOL')) define('MAILHEADER_EOL',"\n");
  * Check if a given mail address is valid
  */
 if (!defined('RFC2822_ATEXT')) define('RFC2822_ATEXT',"0-9a-zA-Z!#$%&'*+/=?^_`{|}~-");
-if (!defined('PREG_PATTERN_VALID_EMAIL')) define('PREG_PATTERN_VALID_EMAIL', '['.RFC2822_ATEXT.']+(?:\.['.RFC2822_ATEXT.']+)*@(?i:[0-9a-z][0-9a-z-]*\.)+(?i:[a-z]{2,4}|museum|travel)');
+if (!defined('PREG_PATTERN_VALID_EMAIL')) define('PREG_PATTERN_VALID_EMAIL', '['.RFC2822_ATEXT.']+(?:\.['.RFC2822_ATEXT.']+)*@(?i:[0-9a-z][0-9a-z-]*\.)+(?i:[a-z]{2,63})');
 
 /**
  * Prepare mailfrom replacement patterns