Shopify requires a passkey for high-security actions like store transfers. Even if you don’t recall setting one up, your Mac likely created one automatically using Touch ID or your system password during two-factor authentication setup. Check System Settings > Passwords on your Mac to see if a Shopify passkey exists.
If the screen remains stuck, the browser may be blocking the verification popup. Switch to Safari, as it integrates most reliably with Mac hardware for passkey prompts.