I am not sure what most of that information has to do with my question. I have a Samsung Samsung Galaxy S7 and he has a Motorola Moto e5. Neither have problems with storage and his is new.
The notification is being sent. With other notifications I was able to go into my desk top application and allow permission for the app or access to settings or whatever. There is a notification for the fact he tried to change the background picture and there is a button for me to click to give him access. I click the button and nothing happens. The box disappears from the screen.
On my devise there is a section that appears to be where I can grant permission for things but nothing comes into that part of my mobile app. I I have to go into my desktop to grant permission through the notification section.
I just want him to be able to change the background picture to his phone. Not too complicated.