When a person try to message another person it hasn t show the message, but it appears this " Received a forbidden error from the server"
Are you using Openfire? Which version. Recently i am seeing lots of strange errors in Spark when using latest versions of Openfire. Not sure where it is coming from though. Maybe Spark is not processing something correctly. But as Spark doesn’t have experienced developer working on it, it will be hard to figure out.