Let's see the most frequent problems you can have while connecting your WooCommerce store to ApiDrop.
WooCommerce is not reachable by ApiDrop:
Even if your WooCommerce website is online and you passed the first connection step that validates your store URL, something could still not working as expected.
Please be sure that Pretty Permalinks are activated as requested by WooCommerce API documentation https://woocommerce.github.io/woocommerce-rest-api-docs/#requirements
To be sure that ApiDrop can reach your WooCommerce API, try to call this URL of your store > http://www.yourstore.com/wp-json/wc/v3 (try using https too).
If you see a page like this, it works, otherwise, something must be fixed.
If your woocommerce is showing this message "Only authenticated users can access the REST API." it could be useful have a look at this page https://stackoverflow.com/questions/50413414/wp-rest-api-and-only-authenticated-users-can-access-the-rest-api and be sure that security plugins like "Sucuri Security" are disabled.
One of the reasons for that error, could be that your website is in "Coming Soon" or "Maintenance" mode. Please switch off this option and publish your website to be sure that the APIs are reachable.
If you think you are doing everything right but WooCommerce won't connect, please contact us using the live chat support button present in your ApiDrop panel.