Download Natwest App For Samsung

I had this problem but found a solution (I use android) I open up the natwest app, then open up chrome and do my shopping. I use the three dashes on the left hand side of my phone ( contextual menu?) To switch between the app and the Web page so I'm not closing down or minimising the Web page. It did work beautifully until now....i have an issue with face recognition it never works?