Unable to connect

I’m currently experiencing a problem with NextDNS. Actually, this problem started some time ago, but I’d like to fix it.

At first, using NextDNS through Private DNS on my phone worked normally on both Wi-Fi and China Telecom’s mobile data network. However, after about one or two weeks, my phone started showing “Unable to connect,” and NextDNS stopped working properly.

I tried many different methods, including reconfiguring my NextDNS profile and even creating a new account, but nothing worked.

Later, I discovered that when I turn on a VPN, NextDNS starts working normally again, and queries appear in the logs. However, without the VPN, NextDNS doesn’t work at all.

I also remember that when I switched to China Mobile’s mobile data network, NextDNS suddenly worked for a short while. However, it eventually stopped working again, and now the only way I can get NextDNS to work is by turning on a VPN.

Interestingly, when I use AdGuard DNS or DUN DNS through Private DNS, they work normally without a VPN.

I really want to solve this NextDNS issue rather than simply switching to another DNS provider. I’m not sure what is causing the problem or where exactly the issue lies.