diff --git a/api/apps/user_app.py b/api/apps/user_app.py
index 1535446d3..0c113dcde 100644
--- a/api/apps/user_app.py
+++ b/api/apps/user_app.py
@@ -354,7 +354,7 @@ def user_add():
     email_address = req["email"]
 
     # Validate the email address
-    if not re.match(r"^[\w\._-]+@([\w_-]+\.)+[\w-]{2,4}$", email_address):
+    if not re.match(r"^[\w\._-]+@([\w_-]+\.)+[\w-]{2,5}$", email_address):
         return get_json_result(data=False,
                                retmsg=f'Invalid email address: {email_address}!',
                                retcode=RetCode.OPERATING_ERROR)