title: Chrome: Cross-origin plugin content from must have a visible size larger than 400 x 300 pixels
body: <p>I am using Google Chrome Version 62.0.3202.94 and recently get this new error message in the developer console:</p>
  
  <p><code>Cross-origin plugin content from  must have a visible size larger than 400 x 300 pixels, or it will be blocked. Invisible content is always blocked.</code></p>
  
  <p>Site: <a href="https://www.matheretter.de" rel="noreferrer">https://www.matheretter.de</a> </p>
  
  <p>Clicking on the error brings me to the first line of the HTML: <code>&lt;!DOCTYPE html&gt;</code> which is not helpful to track down the problem.</p>
  
  <p>Can anyone help?</p>