I receive this error on a page with a button, and only a button and text. I have seen some articles on the internet, but don't really see a good answer. Security is important for my Internet app. This page works fine when I am not autenicated. The web application has a login page, where users login and get authenicated. When I users are authenicated and then access this page, the error occurs. Any suggestions?
Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.