The preview looks great – then the banner silently fails to display on live networks for reasons that were not checked beforehand due to a compatibility issue.
Understand Ad Network Whitelists
They detail out what file types and 3rd party scripts are allowed on each network (ie. Google Display Network vs. Facebook). Make sure to check out the whitelists for the networks that your ad campaign will be on before doing any work on building out the HTML5 banner ad creative.
Check File Weight Limits
Typically there is a very low weight limit for the initial file to be loaded (around 150 KB or so) with later polite loads allowed at a higher weight limit. Again this is typically dictated by the technical requirements for Ad Manager (and often other networks in general).
Confirm Your Animation Library Is Permitted
We can’t stress enough how important it is to check what libraries your HTML Banner Ads have been built with (such as GSAP) and whether these have been approved for use on certain ad networks (e.g. Google Web Designer output has been approved for use on the Google Display Network).
Always Include a Fallback Image
When such a case occurs, usually the web page will remain unchanged – i.e. without any indication that a banner failed to load – which means that a so-called Fallback Image needs to be included for such cases as well. In its most basic form this is nothing but a static, plain version of the HTML banner ad in question. If you want HTML Banner Ads, https://thebannermen.com/banners/animated-ads/html5/ is a good place to start.
By checking these points beforehand, the unnecessary work of redoing the creative can be avoided.