Solution:
First of all, double-click the iOS Project (or put right-click on the iOS Project and then select “Options”)
Afetr that go to section “Build” -> “iOS Bundle Signing”.
Remove entry from “Custom Entitlements”.
Now the application builds fine.
Update: Here is a second option.
First, you'll require an AppleId. In caseyou don't have one already, sign up for one here: appleid.apple.com.
Next, open Xcode. Open Spotlight (Command + Space), Xcode.
Before everything, you'll require to include your AppleID first. Hence at the bar of the top-left of the monitor, click XCode and then click preferences. After that click the accounts tab. Click the + button at the bottom left and include your AppleID account.
Once you have included your AppleID, click on your AppleID and click on Manage Certificates at the bottom right. Following this click the + button and select iOS Development.
Now once it's finished, close the preference window.
Most likely the project had been erroneously saved with a “Custom Entitlements” value for the iPhoneSimulator platform. (One of the older versions of Xamarin.VisualStudio used to do this.) Open up the “Build / iOS Bundle Signing” page for the iOS project settings and blank out any “Custom Entitlements” value for “Platform: iPhoneSimulator” — it probably contains the value “Entitlements.plist”. Rebuild the project; all should now be well.
