Please note: If you have created a brand new portal account you may not have the ability to add SmartThings until we manually add the permission to your account. We are in the process of fixing this bug and new portal accounts will have the SmartThings permission very shortly. Fix should be live on Friday, May 9 or ealier.
If you have created a brand new portal account and don't have the ability to add SmartThings, please send me a Private Message (link under my avatar) or post in this thread and I will fix it immediately.
Very sorry for the inconvenience.