I tried to register an extension for app as learned on https://shopify.dev/tutorials/shopify-app-cli-extension-commands
shopify register --api_key=XXXXXXXX
It returns "You do not have access to this feature".
I could not find any reference about this error. I have tried "shopify logout" and "shopify connect". Nothing seems to help.
Is this because the extension requires Shopify PLUS account?
The extension was created from Argo checkout template
shopify create extension --type=CHECKOUT_POST_PURCHASE
Thanks for any help!