COMMON MISTAKES If, instead of this error message, you get a generic “File not found” exception page, check the syntax of the customErrors section in the Web.config file. Additionally, check that you can successfully view the actual error pages (Error404.aspx and OtherErrors.aspx) by directly requesting them in the browser. If they contain an error (for example, if you forgot to set the page title) they cannot be used as custom error pages.