Here is a solution that should work for this issue. Replace what you have in the code block with the following:
<div id="cit-iframe"style="text-align: center; -webkit-overflow-scrolling: touch; overflow: auto;">
<iframe src="https://hub.catalogit.app/iframe/110"></iframe>
</div>
Then in custom css use:
#cit-iframe iframe {
height: 900px;
width: 100%;
margin: 0;
padding: 0;
border: none;
}
Hopefully this should fix the issue for you.