This is hard to diagnose and is not an issue with my app, but here are a few things to try:
- If you have changed the wifi password on your router, then you need to re-add the devices using the TP-Link app on iOS or Android.
- Try this TP-Link document - How do I move my Kasa device to a different wireless network? | TP-Link
- Your device is having difficulty with a joined 2.4g and 5g wifi:
- Try separating the bands and connect the device to 2.4g.
- Create a 2.4g guest wifi network and connect your TP-Link devices to this network.
- Try switching the device off at the wall, this can force it to connect and report status to the correct TP-Link regional server.