diff --git a/api4/user_test.go b/api4/user_test.go
index fd60a40eec..6b8b149519 100644
--- a/api4/user_test.go
+++ b/api4/user_test.go
@@ -69,6 +69,11 @@ func TestCreateUser(t *testing.T) {
 	CheckErrorMessage(t, resp, "model.user.is_valid.email.app_error")
 	CheckBadRequestStatus(t, resp)
 
+	ruser.Username = "testinvalid+++"
+	_, resp = Client.CreateUser(ruser)
+	CheckErrorMessage(t, resp, "model.user.is_valid.username.app_error")
+	CheckBadRequestStatus(t, resp)
+
 	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.TeamSettings.EnableOpenServer = false })
 	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.TeamSettings.EnableUserCreation = false })
 
diff --git a/i18n/en.json b/i18n/en.json
index bb71f9fcc2..4fd2fa1286 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -4706,6 +4706,14 @@
     "id": "model.user_access_token.is_valid.user_id.app_error",
     "translation": "Invalid user id"
   },
+  {
+    "id": "model.user.is_valid.email.app_error",
+    "translation": "Please enter a valid email address."
+  },
+  {
+    "id": "model.user.is_valid.username.app_error",
+    "translation": "Username must begin with a letter and contain between 3 and 22 characters including numbers, lowercase letters, and the symbols \".\", \"-\", and \"_\"."
+  },
   {
     "id": "model.utils.decode_json.app_error",
     "translation": "could not decode"