Inline Ad Not Previewing or Showing Up When Launched

We've recently implemented a new Wordpress site and we'd like to add a few Inline Ads to some pages. We're not able to preview any inline ads we build through Marketo on the website. They are also not showing up when we launch them on our pages, but we do get impressions as if the ad has been seen. We've all the usual troubleshooting (refreshing, logging out, incognito windows) to and see the ad, but no luck.

Does Marketo not play nice with Wordpress? Are there specifications to the zone-id's that we don't realize?

Any help would be appreciated, thanks!