How to get MP4 files to play? Desktop app / Web

Description

On the desktop app, as well as if we browse to RC, we cannot get MP4 files to show the video content. Only the audio is played. How to fix this?

Server Setup Information

Version 5.4.1
Apps Engine Version 1.36.0
Node Version v14.19.3
Database Migration 281 (January 22, 2023 9:19)
MongoDB 5.0.6 / wiredTiger (oplog Enabled)
Desktop App: 3.8.16 (Windows 11)
Browser: Firefox 109.0