If you haven’t found a solution yet, this is what I had to do to fix the problem:
-deactivate & uninstall the woocommerce plugin. (this will not remove any products you may already have set up)
-go to https://www.ads-software.com/plugins/woocommerce/advanced to download a previous version of woocommerce, 3.9.3
-upload the woocommerce 3.9.3 plugin and activate it.
-log in to your Gooten account to connect your store.
When I did this, it gave me a message that something wasn’t right, but it did connect. After I confirmed the connection, I upgraded back to the current version of woocommerce, and the connection with Gooten still works. It’s a pain in the butt to have to do all this to make it work, so if you don’t have the patience for it, I recommend Printful. Their plugin is much more current and I have zero issues with their integration, and am using them as my primary service. I’m only trying to use Gooten for products that Printful does not have.
Good luck in your endeavor.