The plugin that I'm using is Shopsheriff

I have tried the following:

<!-- AMP iframe --><script async custom-element="amp-iframe" src="https://onetapsignup.com/otg/shopify-script.js?shop=khuba-llc.myshopify.com/v0/amp-iframe-0.1.js"></script>

This is the error I receive:

Any suggestions would be helpful! Thanks in advance!