I see the threads where you say we control the switch from two different devices with the same login, but his isn't happening!

I had the switch on my Android phone and the Kasa app worked fine on it. Then I bought an Iphone and installed the app on the iphone. 

It works on the Iphone, but now the Android phone cannot control it. The app is there, the device is shown, but turning it on/off on the Androld phone no longer works!'

My wife needs to be able to turn the switch on/off when I am not here. This needs to be able to work on two phones!