Google reference can be found here:
https://support.google.com/admanager/answer/7035424?hl=en
Fix it by giving values to minWidth and minHeight
<script data-exports-type="gwd-studio-registration">function StudioExports() {
Enabler.exit("clickTag", "http://desaparkcity.com/southbrooks/");
}</script><script type="text/gwd-admetadata">{"version":1,"type":"GoogleAd","format":"","template":"Banner 3.0.0","politeload":true,"fullscreen":false,"counters":[],"timers":[],"exits":[{"exitId":"clickTag","url":"http://desaparkcity.com/southbrooks/"}],"creativeProperties":{"minWidth":300,"minHeight":250,"maxWidth":0,"maxHeight":0},"components":["gwd-google-ad","gwd-image","gwd-page","gwd-pagedeck","gwd-taparea"],"responsive":true}</script>