NSError domain check condition fails in iOS 8

I am using WKWebView for iOS 8 devices and want to check if the error occuring is NSURLErrorDomain then I want to make some changes, until now, I have added below code, but somehow the compiler goes into else part, now sure why.

- (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    if ( [error domain] == NSURLErrorDomain )
    {
        //code here
    }
    else
    {
        //But compiler always comes here
    }
 }

The error I do get is 'NSURLErrorDomain', but compiler is not executing if loop and goes in else part. Can anyone tell me why it is?