Exception message: Invalid postback or callback argument.

Hello,

Users on our sites are receiving the error detailed below. We recently moved our application from one server to another and this is when the issue seemed to have started. Any ideas?

We are using AJax toolkit, I’m suspecting something didn’t get copied over correctly to new server?

Exception information:

Exception type: ArgumentException

Exception message: Invalid postback or callback argument. Event validation is enabled using 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.

Stack trace: at System.Web.UI.ClientScriptManager.ValidateEvent(String uniqueId, String argument)
at System.Web.UI.Control.ValidateEvent(String uniqueID, String eventArgument)
at System.Web.UI.WebControls.DropDownList.LoadPostData(String postDataKey, NameValueCollection postCollection)
at System.Web.UI.WebControls.DropDownList.System.Web.UI.IPostBackDataHandler.LoadPostData(String postDataKey, NameValueCollection postCollection)
at System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)