Question Extern Dll doesn't work in Visual Studio Project

Hello everyone,

i try to use a self programmed dll which uses the System.ServiceModel namespace.

My steps so far:

• Added the dll to the unity plugins folder
• Added the refference with this post

In Visual Studio all works fine, no IntelliSense Errors appears. But if i push the play button i get the following error:
MethodAccessException: Method `System.ServiceModel.BasicHttpMessageSecurity..ctor()' is inaccessible from method `D3Client.D3Connector..ctor(string,int,string,string,string,string,int,bool)'
D3Client.D3Connector..ctor (System.String ip, System.Int32 port, System.String server, System.String user, System.String password, System.String language, System.Int32 arch, System.Boolean https) (at <55103ac3c64043c9bcdebd6f52b8d1e5>:0)

It seems like the Unity editor doesn't realise the manual added reference.

Have you any idea, how to solve this problem?

Thanks for help.

Best Regards
Sebastian