If the SmartThings app freezes on the splash screen or closes immediately, start with the basics: force-close it, clear the cache (Settings → Apps → SmartThings → Storage), and relaunch. If that doesn't help, check whether your phone's OS is up to date — the app has known issues on outdated Android and iOS builds. Reinstalling usually fixes persistent crash loops.
You tap a switch or thermostat and nothing happens — the device shows as online but ignores commands. This is almost always a hub communication issue.
Routines and automations stop firing without any obvious reason. Open the SmartThings app, go to Automations, and check whether the routine is still enabled — updates sometimes reset toggles. Also verify location permissions if your automation depends on presence detection: the app needs precise location access at all times, not just 'while using'.
The hub appears offline even though it's physically powered on. First, confirm the hub has internet access — plug a laptop into the same network port or switch to verify. If the network is fine, the issue is likely a cloud sync delay. Log out of the app, wait two minutes, and log back in. Persistent offline status may require a factory reset of the hub.
If commands take 5–10 seconds to execute, the bottleneck is usually your home network, not the cloud. Run a quick ping test to your router. SmartThings relies on consistent low-latency connectivity between the hub and your router — Wi-Fi interference from neighboring networks on 2.4 GHz is a common culprit. Switch the hub to a wired Ethernet connection if possible.