After the recent changes at the Shopify platform we had to make some updates to our Shopify Feeds generator.
Shopify has deprecated its private apps. They were not completely removed, they were replaced by custom apps.
Read more about Shopify custom apps
You can still continue using your existing private apps and its credentials with your Shopify feeds. But if you wish to create a new app you will need to work with a custom app.
Learn how to create a custom app and obtain credentials
If you have both private (legacy) and custom (new) apps, you can still use either one. When you authenticate your Shopify store, please use a switcher to choose which app’s credentials you wish to use:
Don’t forget about default settings where you can save your Shopify app credentials. This will make your life easier when generating new feeds: