I have a HS105 smart plug all set up and working on wifi only, signed in properly on my account as well.
On the home screen, it shows that the ddevice is WiFi only. I click into the device and remote control is already turned on. I completely close the app and log back on, and the device shows as WiFi only again, but is already turned on when I go into the settings. I also tried toggling the remote control option. To confirm remote control is not working, I turned off the WiFi on my phone and tried using wireless data to control the smart plug but is not working. I also checked for firmware updates and there are none.