diff --git a/main/inc/lib/api.lib.php b/main/inc/lib/api.lib.php
index b5bca69c30..0688db262d 100755
--- a/main/inc/lib/api.lib.php
+++ b/main/inc/lib/api.lib.php
@@ -302,7 +302,7 @@ define('LOG_SURVEY_CLEAN_RESULTS', 'survey_clean_results');
 
 define('LOG_WS', 'access_ws_');
 
-define('USERNAME_PURIFIER', '/[^0-9A-Za-z_\.\$-]/');
+define('USERNAME_PURIFIER', '/[^0-9A-Za-z_\.@\$-]/');
 
 //used when login_is_email setting is true
 define('USERNAME_PURIFIER_MAIL', '/[^0-9A-Za-z_\.@]/');