This thread is resolved. Here is a description of the problem and solution.
Problem:
The issue here is that the user is being told that they need a valid elegant theme subscription in order to update their toolset plugins.
Solution:
This seems to have been a conflict between toolset and elegant themes. What I recommend that you do is to perform a manual update of the plugins by going to our toolset downloads page and downloading and uploading the plugin manually.
I'm trying to update the Types and Views plugins on my site. When I try, I get the following error for both:
"An error occurred while updating Toolset Types: 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"
My Divi subscription/API is working properly.
I got this error on another site, but after completing all plugin/theme updates, I was then able to complete the Toolset updates. For some reason though on this site, the errors persist.
I briefly switched to the theme Twenty Seventeen, cleared all caches with W3 Total Cache, then attempted to update the Toolset plugins again. I got the same errors again.
I then also removed 2 Elegant Theme plugins, Bloom and Monarch, and then attempted the update again. The error changed to "Update package not available" as seen in toolset_update_error_screenshot_3.png.
I then attempted to update the plugins via the Commercial section of the Add Plugins area. I got a similar error to that above "Update package not available" as seen in toolset_update_error_screenshot_4.png
I've now returned to my Divi-child theme and re-activated Bloom and Monarch. The original error has of course returned.
Uploading the plugin files manually via ftp seems to have worked. Of course whatever was causing the problem isn't necessarily fixed, especially seeing as the errors appeared on more than one site. Hopefully I don't experience the same issue next time there is a Toolset update.