Fix
Meta login opens in a new tab
Continue with Facebook opens a new tab and asks the browser to activate it immediately.
In Manage Connections → Meta Ads → Add New Account, Continue with Facebook opens Meta login in a new tab. Konektor asks the browser to activate the tab immediately.
After login, select the account in Konektor. You can use the button again if you close the login tab early. If the browser blocks the new tab, allow popups for Konektor and try again.