Diagnosis
Yeah, this one's common with a lot of smart appliances. The wireless module in the dryer can be finicky, especially if your home Wi-Fi router is on the other side of the house or there's a lot of interference.
How to Fix It
First, try a full reset of the dryer's network module. On the control panel, press and hold the 'Dryness' and 'Wrinkle Shield' buttons simultaneously for about 3 seconds until the Wi-Fi icon blinks. This clears the old network settings. Then go through the setup in the SmartThings app again, making sure you're entering the exact 2.4GHz network password (these dryers don't connect to 5GHz networks).
If That Didn't Work
The signal might just be too weak. Consider a Wi-Fi range extender placed closer to the laundry area. Also, make sure your router's firmware is up to date. In rare cases, the wireless control board in the dryer itself can be faulty, but that's a last-resort diagnosis.
Heads Up
The smart features are handy for alerts, but they're not critical for operation. The dryer will work perfectly fine on manual cycles even if the Wi-Fi is disconnected. Don't let a flaky connection trick you into thinking the appliance is broken.