Enter your wpdownloadmanager.com username and password, then save settings. After login, it will refresh the page and you will see the list of your plugins.
However, if you are facing problem in that process, you still can download the latest version manually from premium download area https://www.wpdownloadmanager.com/user-dashboard/purchases/ and update plugin.
If you want to me check it in your installation, please give me your wpdownloadmanager.com login info and your site login info in a private reply.