UXP - Fetch call is giving Network Request failed with url behind private VPN

Hi there,
I'm trying to fetch some data I have in a web app that is served in a virtual machine behind my company's internal network. I've whitelisted the url with its host name and ports, but I'm unable to fetch data. The only error I'm seeing "Network request failed", and the strange thing is that when I try to get data from the dev server in localhost, it is working correctly. It's weird because I thought it could be something related to CORS or Nginx, but it also works when I mount all my containers locally. This server is serving data to a CEP app with no more issues.

When I inspect the Network tab in the debugger, I see the request with an error, but if I click on the url there, I can see the JSON data that I need. Am I missing something? Thanks in advance