Your smart home depends on the SmartThings cloud for many things to function. Konnected recommends that you have a backup internet service connected at your home WiFi router in case your primary ISP goes down. One economical way of doing thisis with the following 4G LTE modem from Netgear:
NETGEAR 4G LTE Modem with Two Gigabit Ethernet Ports – Instant Broadband Connection and Automatic 4G LTE/3G Backup (LB2120)
You can connect this device between your broadband modem and router for automatic internet outage failover protection. Youcan often add a data-only plan for this device on to your mobile phone bill for a small additional monthly charge.