Security Exception
Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
System.Security.CodeAccessPermission.Demand() +59
System.Reflection.Assembly.VerifyCodeBaseDiscovery(String codeBase) +118
System.Reflection.Assembly.get_CodeBase() +32
System.Web.Handlers.ScriptResourceHandler.GetCodeBaseWithAssert(Assembly assembly) +31
System.Web.Handlers.ScriptResourceHandler.GetLastWriteTime(Assembly assembly) +36
System.Web.Handlers.ScriptResourceHandler.GetAssemblyInfoInternal(Assembly assembly) +58
System.Web.Handlers.ScriptResourceHandler.GetAssemblyInfo(Assembly assembly) +59
System.Web.Handlers.RuntimeScriptResourceHandler.System.Web.Handlers.IScriptResourceHandler.GetScriptResourceUrl(Assembly assembly, String resourceName, CultureInfo culture, Boolean zip, Boolean notifyScriptLoaded) +336
System.Web.UI.ScriptManager.GetScriptResourceUrl(String resourceName, Assembly assembly) +114
System.Web.UI.ScriptRegistrationManager.RegisterClientScriptResource(Control control, Type type, String resourceName) +115
System.Web.UI.ScriptManager.RegisterClientScriptResource(Control control, Type type, String resourceName) +9


Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

Request for the permission of type 'System.Security.Permissions.FileIOPermission
Actually it was none of those. You can't access the web.config appsettings using: System.Web.Configuration.WebConfigurationManager on medium trust. I changed it to System.Configuration.ConfigurationManager after a couple hours of researching and it is fine now.

Get a new host. They have not setup their web host properly. Sorry, I cannot assist further.

Sorry may I ask exactly what you mean by "They are not supporting AJAX extensions."

I am running into same problem with latest YAF, again, 1and1 and my hosting provider.