Iframes Not Working

Hey guys,

I can’t seem to get iFrames to work either. The onebox for youtube as an example works great, but whenever we post links they are not showing up like this:

I can see a loading circle to the left of a link when composing a post, but it ultimately just displays the actual link and not the iframe.

I checked a few other threads and have tried suggested troubleshooting (accessed the site in safe mode, added specific domains to the allowed iframes admin setting) but NO links are becoming iframes.

Could there be another setting in the admin that is preventing this from working properly?