Android (Xaoimi Redmi 9), cleanbrowsing only works when connected to wifi

Thanks for your reply. With the phone it data mode, I opened the cleanbrowsing app to disable it. On the home screen it had “family filter” checked in grey and at the bottom, it said “blocking enabled.” I went to the setting screen, and “enable auto start” was in green. I didn’t see a button to disable, so I clicked the “change pin” button to see what would happen. It asked me for my pin. When I entered it, I noticed that the VPN box appeared among the icons at the top of the screen, where before it was only appearing with wifi. I’ve tried turning on and off the wifi several times, and the VPN doesn’t disappear and the filtering works. So, somehow, it seems that the VPN was turning itself off, even though the cleanbrowsing app said that it was enabled. How could this be?

In experimenting with this, I tested the “enable auto start” button, to make sure my son wasn’t able to turn it off. When I click it, it asks me for the pin. I put in the wrong pin. It says “wrong pin” but turns the “enable auto start” off anyway (the button slides to the left and goes grey). I wonder if somehow my son was turning this off without me realizing it (although it was marked as green/enabled when I took his phone from him to work on this and the VPN wasn’t on. And also he’s not very sophisticated yet). How can I make sure he doesn’t turn off the filter or that it doesn’t turn itself off?

Thanks!