Cannot read property 'Keyboard' of undefined


Suddenly (without changing anything I can think of) I get an error in my console "Cannot read property ‘Keyboard’ of undefined"
I tried executing cordova plugin add com.ionic.keyboard but it gives me another error "Registry returned 404 for GET on"
My IDE (webstorm) does recognize the “keyboard” in my app.js after executing cordova plugin add ionic-plugin-keyboard, but I still get the error in my console.

How can I solve this?