Touch screen remote operations mobiles

Dear Teamviewer

I frequently need to help my 93 year old mum use her smart phone.

I have been using your excellent quick support TeamViewer remote control for several years, but recently it will not let me interact directly with her screen. It shows me, and her, a blue finger wherever I move it to, but she then has to touch the screen where I try to show her with the pointing blue cursor. It's far from ideal.

What am I doing differently or why can I not move around for her the way I used to? Screenshot attached of settings showing touch mode selected. 

Thank you for your help

Sara