EMDK for Xamarin,  error: cannot find symbol at compiling time

Hi, I'm trying to compile my application using VS2017 and I get errors:

 

error: cannot find symbol  com.symbol.emdk.EMDKManager.StatusListener

symbol:   class StatusListener

location: class EMDKManager

\obj\Debug\android\src\mono\com\symbol\emdk\EMDKManager_StatusListenerImplementor.java

 

error: cannot find symbol

public void onStatus (com.symbol.emdk.EMDKManager.StatusData p0, com.symbol.emdk.EMDKBase p1)

symbol:   class StatusData

location: class EMDKManager

\obj\Debug\android\src\mono\com\symbol\emdk\EMDKManager_StatusListenerImplementor.java

 

error: cannot find symbol

private native void n_onStatus (com.symbol.emdk.EMDKManager.StatusData p0, com.symbol.emdk.EMDKBase p1);

symbol:   class StatusData

location: class EMDKManager

\obj\Debug\android\src\mono\com\symbol\emdk\EMDKManager_StatusListenerImplementor.java

 

I'm using the Symbol.XamarinEMDK  Runtime Version  v4.0.30319,  Version  2.3.0.43

My application target framework is MonoAndroid v7.1.

 

The BarcodeSample1 works.

 

Is there anyone that can help me?

Thanks!