Private dns on ANDROID 9 not working

https://1.1.1.1/help#eyJpc0NmIjoiWWVzIiwiaXNEb3QiOiJObyIsImlzRG9oIjoiTm8iLCJyZXNvbHZlcklwLTEuMS4xLjEiOiJZZXMiLCJyZXNvbHZlcklwLTEuMC4wLjEiOiJZZXMiLCJyZXNvbHZlcklwLTI2MDY6NDcwMDo0NzAwOjoxMTExIjoiWWVzIiwicmVzb2x2ZXJJcC0yNjA2OjQ3MDA6NDcwMDo6MTAwMSI6IlllcyIsImRhdGFjZW50ZXJMb2NhdGlvbiI6IkJPTSIsImlzcE5hbWUiOiJHb29nbGUiLCJpc3BBc24iOiIxNTE2OSJ9
Please check the url above.
I have set the private dns using the instructions on Cloudflare blog but still the 1.1.1.1/help doesn’t show.

Seems you have a VPN active. Private DNS will at least not work with OpenVPN. I guess this counts for any active VPN connection, not only OpenVPN.

Try to get rid of any DNS server that’s being pushed through the tunnel. But i don’t know if it makes any difference.

I am using adguard 24x7. And under it’s dns setting I have selected cloud flare.
Does it still make a difference in selecting private dns?

It is a known Android bug. With private DNS you have always connection problems, regardless of the DoT server. Some servers somewhat better, some are worse, but with all have serious connection problems on Android 9. I have OP 6T, I tried plenty of DoT servers, but none of them worked completely