Title: Android Private DNS loses connectivity only with NextDNS

Hello,

I am experiencing an issue with NextDNS when using Android Private DNS (DNS-over-TLS).

Configuration ID: 74e318

Device:

• Motorola Edge 30 Pro

Country:

• Argentina

ISP:

• TDC NET

Problem:

After configuring Android Private DNS with:

74e318.dns.nextdns.io

the connection works correctly for a few minutes. After some time, Android displays the following message:

"Cannot reach the private DNS server"

At that point, the Wi-Fi network becomes limited and internet access stops working until I disable Private DNS or switch to another DNS provider.

Tests performed:

• Cloudflare Private DNS (one.one.one.one) works correctly.

• Google Private DNS (dns.google) works correctly.

• NextDNS works correctly when using mobile data.

• The issue persists even after creating a brand new NextDNS profile with no blocklists or custom settings.

• Android network settings were completely reset.

• The issue occurs on different Wi-Fi access points connected to the same ISP.

• The issue occurs both on Wi-Fi and through a secondary TP-Link access point connected to the main router.

Router:

• Huawei HG8247H5

PC tests performed from the same internet connection:

nslookup dns.nextdns.io

Result:
Resolution successful.

nslookup test.nextdns.io 1.1.1.1

Result:
45.11.105.129

curl https://nextdns.io

Result:
Works correctly.

curl -4 https://test.nextdns.io

Result:
curl: (28) Failed to connect to test.nextdns.io port 443 after approximately 21 seconds: Could not connect to server

Additional observations:

• test.nextdns.io works correctly when using mobile data.

• test.nextdns.io does not work from my home internet connection.

• Android only reports "Cannot reach the private DNS server" when using NextDNS.

• Cloudflare and Google DNS-over-TLS work normally and do not cause connectivity issues.

• The problem can be reproduced consistently.

Based on the tests above, this does not appear to be related to my Android configuration, device settings, blocklists, or NextDNS profile configuration.

Could this be a routing, peering, Anycast, or server reachability issue affecting connectivity between my ISP and the NextDNS infrastructure?

Thank you for your help.