How to fix error system.security.securityexception: request failed. Server host

Server Error in '/' Application.
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 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 failed.]
   System.Security.CodeAccessSecurityEngine.ThrowSecurityException(RuntimeAssembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +96
   System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +80
   System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, Object assemblyOrString, SecurityAction action, Boolean throwException) +288
   System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, RuntimeAssembly asm, SecurityAction action) +70
   System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type) +0
   System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName) +70
   System.RuntimeType.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark) +40
   System.Type.GetType(String typeName) +30
   System.CodeDom.Compiler.CompilerInfo.get_IsCodeDomProviderTypeValid() +12
   System.Web.Compilation.CompilationUtil.GetRecompilationHash(CompilationSection ps) +2045
   System.Web.Configuration.CompilationSection.get_RecompilationHash() +107
   System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDateInternal(Int64 cachedHash) +458
   System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate(Int64 cachedHash) +51
   System.Web.Compilation.BuildManager.ExecutePreAppStart() +135
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +549

How to Fix  Error System.Security.SecurityException: Request failed. server host