This issue has been resolved. Wordpress domains can now be added without issue. It's possible that if a WP domain was added during this issue it may be stuck in a "configuring" state in Unbounce. Our developers will be fixing these domains as soon as possible. If an immediate fix is required the domain can be deleted and re-added within the Unbounce account.
We apologize for any inconvenience this issue has caused. If you are still experiencing issues with your domain please contact our support team at firstname.lastname@example.org