Looks like a new version of the android mobile app is about to be released
This issue appears to have only impacted customers with SmartThings Hubs and the last version of the Android mobile app. We have released an Android update (version 1.7.34-26) to correct this issue. This update is rolling out to all users over the next couple of days and we will monitor error rates to confirm the issue is fully resolved.
Posted about 3 hours ago. Jun 25, 2019 - 12:30 EDT
Some North American and European users may currently be unable to add the SmartThings Hub 2018 model, receiving the error “Hub not found.” We are currently investigating and will provide updates as available.
Posted 14 days ago. Jun 11, 2019 - 15:01 EDT