It’s not possible to use that tool to migrate followers to a WordPress.com site. It can only transfer followers away from a WordPress.com site, or between self-hosted sites.
example.wordpress.com is not your site. Can you please provide the exact addresses of the sites between you did the migration, as well as the exact addresses of the sites between which you want to migrate the subscribers? Please clearly indicate which site is the FROM and which site is the TO in each case.