Script tag not appearing?

I am trying to add a Native Amazon Ad block into my posts. It works on a couple other OeanWP theme websites I have; however, it doesn’t work on this one website I have.

It should appear before the first H2 title of every article – I use Ad Inserter plugin. I contacted the plugin support for Ad Inserter and they told me the <script.. part was not appearing.

I insert the below in full:

<div id=”amzn-assoc-ad-228e1530-5585-45d3-8330-8825c29b61cc”></div><script async src=”//z-na.amazon-adsystem.com/widgets/onejs?MarketPlace=US&adInstanceId=228e1530-5585-45d3-8330-8825c29b61cc”></script>

However, when I inspect before the first H2 title in the article, I see the <div> part
<div id=”amzn-assoc-ad-228e1530-5585-45d3-8330-8825c29b61cc”></div>

but the rest of it <script async src=… is not appearing.

The plugin rep told me “Maybe because of some security plugin or security setting on the server.”

I contacted my host whosaid there is noting wrong on their end. I tried disabling each ofmy plugins including my security plugin and still that <script.. part is not appearing.

Any idea why? Thanks in advance

The page I need help with: [log in to see the link]