I am receiving this error when I click on the button to log into Facebook from my website.
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.
When searched Google and found these two links so I can understand the error message. However they did not fix the problem.
asp.net: Invalid postback or callback argument
So I took apart the page section by section until I found what was causing the error. It was this:
iframe name="ContentIFrame" class="IFrameStyle"
When I delete the iframe, everything works. However, I need the iframe on the page. Can anyone assist why the iframe is causing this error? It has nothing to do with Postback.