[🐞] Partytown Shopify Integration Failed to execute 'postMessage' on 'Worker'

[AnalystCS7]

Describe the bug

hi!
I have been through the guide to set up partytown on a shopify 2.0 store but am now facing an error that I'm not quite sure how to handle.
I have created the proxy app on shopify and have set up the worker on cloudflare.
However, when I check the console I see the following error:

Any idea what the issue is?

Reproduction

NA

Steps to reproduce

Following this guide:
https://github.com/edlaver/cloudflare-worker-partytown-shopify-app-proxy/tree/main

Browser Info

Chrome

Additional Information

No response