Risolto (grazie a ChatGPT)
codice:
<td align=center  valign=top>
    <div style="width: 720px; height: 720px; overflow: hidden;">
       <iframe src="http://xxxxx.yyyyy.com:1234" width="1920" height="1088" frameBorder="1"  scrolling="no" style="transform: translate(-270px, -225px);">
       </iframe>
    </div>
  </td>