Web player build error

Questions & Answers
1

Web player doesn’t build with error in Editor.log:

    -----CompilerOutput:-stdout--exitcode: 1--compilationhadfailure: True--outfile: Temp/Assembly-CSharp.dll
    
    The class System.Security.SecurityCriticalScope could not be loaded, used in mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
    
    Can't find custom attr constructor image: G:\dev\unity\Assets\Assemblies\MonoAddins\System.Runtime.Serialization.dll mtoken: 0x0a0002d8
    
    -----CompilerOutput:-stderr----------

Error in Unity Editor:

Internal compiler error. See the console log for more information. output was:
Unhandled Exception: System.Reflection.ReflectionTypeLoadException: The classes in the module cannot be loaded.

  at (wrapper managed-to-native) System.Reflection.Assembly:GetTypes (bool)

  at System.Reflection.Assembly.GetTypes () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.RootNamespace.ComputeNamespaces (System.Reflection.Assembly assembly, System.Type extensionType) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.RootNamespace.ComputeNamespace (Mono.CSharp.CompilerContext ctx, System.Type extensionType) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.GlobalRootNamespace.ComputeNamespaces (Mono.CSharp.CompilerContext ctx) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.LoadReferences () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.Compile () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.Main (System.String[] args) [0x00000] in <filename unknown>:0

Standalone(PC/Mac) version build and work fine.
Can someone help me with this problem?

2

I found a solution to the problem. It was 2 different simple .cs script in Unity. I removed first unnecessary script from project, then I converted second necessary script to dll, and now Web player build is ok.