diff --git a/client/i18n/locales/chinese-traditional/translations.json b/client/i18n/locales/chinese-traditional/translations.json
index 39932bf90d..3080bc4d3f 100644
--- a/client/i18n/locales/chinese-traditional/translations.json
+++ b/client/i18n/locales/chinese-traditional/translations.json
@@ -102,6 +102,7 @@
       "contains invalid characters": "用戶名 \"{{username}}\" 含有無效字符",
       "is too short": "用戶名 \"{{username}}\" 太短",
       "is a reserved error code": "\"{{username}}\" 是錯誤代碼，不可用作用戶名",
+      "must be lowercase": "Username \"{{username}}\" must be lowercase",
       "unavailable": "用戶名不可用",
       "validating": "驗證用戶名......",
       "available": "用戶名可用",
diff --git a/client/i18n/locales/chinese/translations.json b/client/i18n/locales/chinese/translations.json
index 85804f3c56..be618d648c 100644
--- a/client/i18n/locales/chinese/translations.json
+++ b/client/i18n/locales/chinese/translations.json
@@ -102,6 +102,7 @@
       "contains invalid characters": "用户名 \"{{username}}\" 含有无效字符",
       "is too short": "用户名 \"{{username}}\" 太短",
       "is a reserved error code": "\"{{username}}\" 是错误代码，不可用作用户名",
+      "must be lowercase": "Username \"{{username}}\" must be lowercase",
       "unavailable": "用户名不可用",
       "validating": "验证用户名......",
       "available": "用户名可用",
diff --git a/client/i18n/locales/espanol/translations.json b/client/i18n/locales/espanol/translations.json
index 3dad1a0a13..797c82a8e6 100644
--- a/client/i18n/locales/espanol/translations.json
+++ b/client/i18n/locales/espanol/translations.json
@@ -102,6 +102,7 @@
       "contains invalid characters": "El nombre de usuario \"{{username}}\" contiene caracteres inválidos",
       "is too short": "El nombre de usuario \"{{username}}\" es demasiado corto",
       "is a reserved error code": "El nombre de usuario \"{{username}}\" es un código de error reservado",
+      "must be lowercase": "Username \"{{username}}\" must be lowercase",
       "unavailable": "El nombre de usuario no está disponible",
       "validating": "Validando nombre de usuario...",
       "available": "El nombre de usuario está disponible",