Security Exception

I couldn't figure out how to fix this error. I am using Visual Studio 2015, .Net 4.52, MVC, entity framework, Microsoft Identity, Bootstrap, and ASP Webforms. I got the following error:
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) +166
System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +100
System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, Object assemblyOrString, SecurityAction action, Boolean throwException) +272
System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, RuntimeAssembly asm, SecurityAction action) +55
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) +39
System.Type.GetType(String typeName) +32
System.CodeDom.Compiler.CompilerInfo.get_IsCodeDomProviderTypeValid() +10
System.Web.Compilation.CompilationUtil.GetRecompilationHash(CompilationSection ps) +2085
System.Web.Configuration.CompilationSection.get_RecompilationHash() +107
System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDateInternal(Int64 cachedHash) +465
System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate(Int64 cachedHash) +51
System.Web.Compilation.BuildManager.ExecutePreAppStart() +132
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +521


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34274