We have resolved the issue. In the ad code in the line <script async src="//www.adplugg.com/serve/js/ad.js"></script> should be <script async src="http://www.adplugg.com/serve/js/ad.js"></script> instead.
Hi,
We have just sign up for free plan to test the ad server, so if meets requirements to upgrade to pro. We have made test image ads but they don't show when we insert the ad code in to site.
Can you please advice.
Thanks