Try these pages:
I have asked someone to setup a proxy server using Squid.
Question: how do I make a fetch request on the wix web module via a Squid proxy?
Have a read of these pages.
Wix Code: Calling Server-Side Code from the Front-End with Web Modules
Wix Code Tutorial: Sending an Email on Form Submission
Wix Code: Accessing 3rd-Party Services with the Fetch API
Connect wix website to a server
Nginx proxy Wix site shows only blank page in browser or not found
Any luck with this?