When i attempted to build my solution, i received this error.
Could not find android.jar for API Level 25. This means the Android SDK platform for API Level 25 is not installed. Either install it in the Android SDK Manager (Tools > Open Android SDK Manager…), or change your Xamarin.Android project to target an API version that is installed. (C:\Program Files (x86)\Android\android-sdk\platforms\android-25\android.jar missing.)
You can go into C:\Program Files (x86)\Android\android-sdk and run SDK Manager in administrator mode and find the corresponding version and enable it.
Rebuild your solution and it will work