UnityWebRequest ConnectionError in 2021 LTS but not 2020 LTS, WebGL

[aer0ace]

HTTP error 500 in WebGL build while fetching localhost URL using Unity 2021 UnityWebRequest

Hello. We are having some troubles resolving HTTP error trying to load some local files in the WebGL build made with Unity 2021.3.6f1 and bundled with a Javascript application running in the browser. Error code is 500 WebGL client is using UnityWebRequest to fetch a file from localhost. After request fails webRequest.result field has value Connection Error, webRequest.error filed has value Unknown Error Example of URL used: https://127.0.0.1:8000/@/artifacts/loader/empty-scenes/contents/QmQye…

This is actually exactly what’s happening with my build. Has anyone else experienced this problem?