Embedding an iFrame into Qualtrics

I am trying to embed an iFrame with this code

<div style="position:relative;overflow:hidden;width:100%;height:600px;"><iframe src="https://pbstanford.org/durham2023-vote-pb" style="position:absolute;top:0;left:0;bottom:0;right:0;width:100%;height:100%;border:5px solid black"></iframe></div>

but am getting an error message that reads “pbstanford.org refused to connect.”

can anybody help troubleshoot?

Thank you!