Changed to more descriptive text that I think what it means at models/users.js

i18n/en.i18n.json

@@ -183,7 +183,7 @@
     "error-json-schema": "Your JSON data does not include the proper information in the correct format",
     "error-list-doesNotExist": "This list does not exist",
     "error-user-doesNotExist": "This user does not exist",
-    "error-user-notAllowSelf": "This action on self is not allowed",
+    "error-user-notAllowSelf": "You can not invite yourself",
     "error-user-notCreated": "This user is not created",
     "error-username-taken": "This username is already taken",
     "export-board": "Export board",