Mismatch between the processor architecture

Hi.
I am using Xamarin.Forms on Visual Studio 2017. I am trying to use a dll that is compiled on 64bit. When i run the app on android emulator, it has a warning of "mismatch between the processor architecture" and the app crashed on the emulator. If i disable the initialization of the said dll, app runs fine.

Is it possible to use external dll's or api's on xamarin and if yes, how can we use those properly on xamarin.

Thanks...