https://www.tp-link.com/en/faq-2233.html

Forget network on your phone, reconnect. Check IP address, use DHCP instead of static IP address. If you connect the smart phone to the host network of your router, would it work?

When the indicator is off on kasa app, if you tap on the switch, what would it say? There should be error message. HS210 is three way switch. If you press power button on swtich A, the white circle...

Check firmware version. See if there is available firmware update https://www.tp-link.com/en/faq-2325.html

Not understand that language myself, but I've seen that error. You need to update firmware. If firmware is latest, contact tplink tec team, they can fix it

So you cannot login kasa with your kasa account? If the hs100 is not bound to your account, you cannot enable remote control. But the other hs100 is working, so that confused me.