Google Pixel 6A will not allow private DNS since 03/10/24

Hi.

As the title, I use NextDNS to manage my daughter's phone. It has worked perfectly right up until 03/10/24 when it suddenly stopped logging.

I checked the phone and the toggle had gone from the Private DNS tab to Automatic.

I have tried to put it back on WiFi and on Mobile but it will not allow it to be selected. I did re-type the i.d in the box just incase she had edited it by mistake but it was correct and still will not allow it.

Anyone any suggestions? Can installed apps mess with the OS DNS settings? I know they can bypass like TikTok etc but not sure they can break them altogether?

Thanks.