The app has always been working with no complaints and has not needed any update for a long while.

So Server.StatusOK isn't true for some reason
In the waiting and in the case someone can spot anything obvious I've missed, here's my login script:

inline function login()
{
    Server.setBaseURL(BASE_URL);
    
    Log.add("Reaching customer account...", "default");
    
    Server.setHttpHeader("");
    
    local parameters = {"username": usernameInputLbl.getValue(),
                        "password": passwordInputLbl.getValue()};
                        
    Server.callWithPOST("wp-json/jwt-auth/v1/token", parameters, function(status, response)
    {
        user = response;
        
        Console.print(trace(response));
        
        if (status == Server.StatusOK)
        {
            Log.add("Successfully connected", "success");

            // do some UI actions... 
        }
        else
        {
            connected = false;
            Log.add("Impossible to login...", "warning");
        }
    });
}

The user doesn't use any VPN or firewall. The location is Australia and I am waiting for more information about the macOS version, IP, and a more detailed log from my app.

The idiot I am forgot to add the status and response to the log...