Not receiving data from postMessage in embedded iframe

Yes, I looked into them. The velo code is taken exactly from there.
The React code is what I wrote in the post and it behaves similarly to the html in the EXAMPLE. That code is run on the initial render of this component (you can read about the useEffect hook here ) and is working as expected (I’m able to use postMessage to send data to other websites), so the problem is most definitely in the wix site.