--- idea-cluster-manager-2024.4.2/ideaclustermanager/app/accounts/auth_constants.py
+++ idea-cluster-manager-2024.4.2/ideaclustermanager/app/accounts/auth_constants.py
@@ -11,4 +11,4 @@
 
 DEFAULT_LOGIN_SHELL = '/bin/bash'
 USER_HOME_DIR_BASE = '/home'
-USERNAME_REGEX = r'^(?=.{3,20}$)(?![_.])(?!.*[_.]{2})[a-z0-9._]+(?<![_.])$'
+USERNAME_REGEX = r'[a-zA-Z0-9_.][a-zA-Z0-9_.-]{1,20}'