System.Reflection.Emit error during build android apk

Hi,

I'm using signalR in my project. I have no problem or error during the development or hitting play in the editor. However, the error come when I'm trying to build it into apk file.

 ArgumentException: The Assembly System.Reflection.Emit is referenced by Microsoft.AspNetCore.SignalR.Core ('Assets/Plugins/Microsoft.AspNetCore.SignalR.Core.dll'). But the dll is not allowed to be included or could not be found.
 UnityEditor.AssemblyHelper.AddReferencedAssembliesRecurse (System.String assemblyPath, System.Collections.Generic.List`1[T] alreadyFoundAssemblies, System.String[] allAssemblyPaths, System.String[] foldersToSearch, System.Collections.Generic.Dictionary`2[TKey,TValue] cache, UnityEditor.BuildTarget target) (at C:/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:152)
 UnityEditor.AssemblyHelper.FindAssembliesReferencedBy (System.String[] paths, System.String[] foldersToSearch, UnityEditor.BuildTarget target) (at C:/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:192)
 UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

It seems like something is wrong with System.Reflection.Emit but I can't figured out what exactly is wrong since I'm still quite new to this. Really appreciate if someone can help me. Thank you