Dear team
I do faced same issue, I am not able to download the document even i am logged in as an administrator.
even after changing the appearance to force download i am not able to download the document.i am getting same error "You are already logged in as admin, you need to log out before logging in as different user.".
I am using Moodle 3.1.2 (Build: 20160912). And this problem is not there in the previous version.
use previous versions is the only one solution infront of me.
Please provide some solution to resolve it ASAP.