Unable to create and install pgAgent service

I'm trying to install pgAgent on my device. During the installation using the stackbuilder, the last step requires me to add the operating system username and password as below: However, after entering the password of my postgres superuser account, i'm shown the below dialog box: Every resource available online mentions that the username and password should be the superuser's. I've tried using the Windows account details as well as creating a new user within postgres and using its details. Any help would be greatly appreciated. I'm using PostgreQL v13, and pgAgent v4.2.1