Unifi - content filtering, android private DNS

A couple days ago, my son's phone started displaying Private DNS cannot be accessed when trying to connect to the kids network. I have a UDMSE and it has content filtering, its been working for months and decided to stop. Is there a work around to allow NextDNS to be accessed, I'd rather have multiple content filters from different sources then rely on just one.

Or did something change where the networks NextDNS is blocking NextDNS on his phone since blocking bypass methods has been enabled this whole time?