After disabling all overlays, restart Steam and test the game.
Before we start fixing things, it helps to understand why this happens. The Steam API (Application Programming Interface) is a set of tools that allows Just Cause 4 to communicate with Steam. This communication handles achievements, cloud saves, friends lists, and most importantly, DRM (Digital Rights Management) verification. just cause 4 unable to initialize steam api
In Windows 10 and 11, security permissions can sometimes prevent games from accessing necessary network ports or system files required to initialize the Steam API. giving both Steam and the game administrative privileges can bypass this restriction. After disabling all overlays, restart Steam and test