I get the following error when updating:

Updating Plugin ARI Fancy Lightbox (1/1)
Downloading update from…
Unpacking the update…
Installing the latest version…
Plugin update failed.
An error occurred while updating ARI Fancy Lightbox: The package could not be installed. The package contains no files.

Initially it failed because it required the API of Theme. At least that was the error message. After adding the API of my theme, it seems to get the wrong files. I have the free version and no need to upgrade. Why do I need an API?

Please advise.

When trying to update without API (which I should'nt need as I have the free version) I get this:

Updating Plugin ARI Fancy Lightbox (1/1)
An error occurred while updating ARI Fancy Lightbox: Before you can receive product updates, you must first authenticate your Elegant Themes subscription. To do this, you need to enter both your Elegant Themes Username and your Elegant Themes API Key into the Updates Tab in your theme and plugin settings. To locate your API Key, log in to your Elegant Themes account and navigate to the Account > API Key page. Learn more here. If you still get this message, please make sure that your Username and API Key have been entered correctly

What has your product to do with my Elegant Themes subscription?

Hello,

The plugin doesn't require any subscription to 3rd party themes. It is enough to enter API key from "Member Area" on our site in plugin settings. If you have any strange message about subscription to 3rd party product, it seems this message is shown by this product.

Regards,
ARI Soft