title: Ionic 4 not opening external/default emailing app on IOS device, whilst working on Android
body: <p>I have written a button to open the phone's default emailing app from my app. It currently works for android and does not work at all for IOS. I am not sure what is wrong and there is not too much information online about this topic. If anyone could guide me, I would be grateful.</p>
  
  <p>Code I have tried and it fails for IOS and works for Android are as follows:</p>
  
  <pre><code>&lt;ion-button expand="block" (click)="emailTest()"&gt;
     &lt;ion-label&gt;help@test.co.nz&lt;/ion-label&gt;
  &lt;/ion-button&gt;
  
  emailTest(){
    this._platform.ready().then(() =&gt; {
        window.open('mailto:help@test.co.nz');
    });
  }
  </code></pre>
  
  <pre><code>&lt;ion-button expand="block"&gt;
     &lt;a href="help@test.co.nz" style="color:white" &gt;help@test.co.nz&lt;/a&gt;
  &lt;/ion-button&gt;
  </code></pre>
  
  <pre><code>&lt;ion-button expand="block" (click)="emailTest()"&gt;
     &lt;ion-label&gt;help@test.co.nz&lt;/ion-label&gt;
  &lt;/ion-button&gt;
  
  emailTest(){
    window.open("mailto: help@test.co.nz",'_system');
  }
  </code></pre>