Download Failed: Unauthorized

This is happening either because the license key is expired or it is not activated on the URL the add-on is installed on. This can sometimes happen if you install the plugin and activate the license key on a temporary URL and then update the site to the final URL.

There are two options you can do to resolve this:

1. Log into your WP Codeus account, click on the License Keys tab, then click on the Manage Sites link for the license key. From that page you will be able to add or remove URLs  for the license. Once the proper URL is registered on the license key, you will be able to install the update.
If your license key is expired, you will need to renew it before you can install the update. The status of your license key will be shown on the License Keys tab of your account page.

2. On the Activate License page, copy the license key to your clipboard and delete it from the license key field and click save. This will reset all parameters. Once you hit save and the field is empty, paste in the license code and hit save again. You will now be able to authorize the final URL. Once the proper URL is registered on the license key, you will be able to install the update.