网页在单击后退按钮时到期

I am working on a Website on ASP.NET using C#. Most of its pages are displaying data in a Grid View and in Crystal Reports. Every time I click back button from Crystal Report page or any other page for going to the previous page which was displaying data in a GridView the webpage displays the message "Webpage has expired" in all the browsers. Is there any way to solve this issue? any help will be really useful.I am working on a Website on ASP.NET using C#.