Problem with connection android to android

Goodafternoon, 

I'm new here and I don't know if I'm posting on the right board. Sorry for that. 
I'm using Teamviewer for my mothers android phone. If she has some problem I connect with my android phone and I can solve the problem. 
Now for Christmas she has got an other phone. Wiko View. (wiko is supported in the devicelist)Also with android (latest). 
I've installed quickviewer and also the add-on. 
When I ask the permission to connect, she accepts but at the same time I've got a message that she refused the permission. And no connection is estabilished

Is there something I missed? With my other devices there is no problem connecting. 

thank you

 Caroliene