Feedback
In mainland China, open the Android phone’s Settings → Network & internet → Advanced → Private DNS, then Select the “Private DNS provider hostname” option, then fill in one.one.one.one, and click Save. Then the words “Unable to connect” appear below the “Private DNS” option. After repeated tests, the three network operators in mainland China, namely “China Mobile”, “China Telecom”, and “China Unicom”, all provide networks that cannot access https://one.one.one.one. I hope it will be fixed as soon as possible.
I don’t know English, my native language is Chinese, so I translated the feedback I wrote into English on a translation website.