diff --git a/locales/en.json b/locales/en.json
index 64a5e6bf3..50561cc80 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -501,6 +501,7 @@
     "invalid_number": "Must be a number",
     "invalid_number_max": "Must be lesser than {max}",
     "invalid_number_min": "Must be greater than {min}",
+    "invalid_password": "Invalid password",
     "invalid_regex": "Invalid regex:'{regex}'",
     "invalid_shell": "Invalid shell: {shell}",
     "ip6tables_unavailable": "You cannot play with ip6tables here. You are either in a container or your kernel does not support it",
@@ -561,6 +562,7 @@
     "log_user_permission_update": "Update accesses for permission '{}'",
     "log_user_update": "Update info for user '{}'",
     "mail_alias_remove_failed": "Could not remove e-mail alias '{mail}'",
+    "mail_already_exists": "Mail adress '{mail}' already exists",
     "mail_domain_unknown": "Invalid e-mail address for domain '{domain}'. Please, use a domain administrated by this server.",
     "mail_forward_remove_failed": "Could not remove e-mail forwarding '{mail}'",
     "mail_unavailable": "This e-mail address is reserved for the admins group",
diff --git a/src/portal.py b/src/portal.py
index de852f5a6..ece555cd5 100644
--- a/src/portal.py
+++ b/src/portal.py
@@ -199,8 +199,10 @@ def portal_update(
 
             try:
                 ldap_interface.validate_uniqueness({"mail": mail})
-            except Exception as e:
-                raise YunohostError("user_update_failed", user=username, error=e)
+            except YunohostError:
+                raise YunohostValidationError(
+                    "mail_already_exists", mail=mail, path=f"mailalias[{index}]"
+                )
 
             if domain not in domains:
                 raise YunohostValidationError(