AdGuard account login requires dns11.quad9.net

[privacy-advo]

AdGuard VPN Browser Extension version

2.5.4

Browser version

Brave 1.78.97 (stable) + Brave 1.79.97 (beta)

OS version

Win11 Pro 24H2

Issue Details

Steps to reproduce:

1. Block dns11.quad9.net on network level
2. Try to login

Expected Behavior

Login successful

Actual Behavior

Login error, please contact service-email

Additional Information

Unblocking dns11.quad9.net fixes the issue.
Blocking DoT/DoH servers to prevent applications (browser etc.) bypassing default DNS is crucial for security.

[alexx7311]

@privacy-advo, hello! Please do the following:

1. Right click the AdGuard VPN extension icon in your browser's toolbar and enable Debug logs.
2. Reproduce the problem and remember the exact time when the issue was reproduced.
3. Right click the AdGuard VPN extension icon again and click Export logs.
4. Send the archive with the file to qa@adguard.com:
   - include [extension] keyword and 216 in the subject of your email
   - specify the exact time when the issue occurred

[ameshkov]

We don't need any logs, the issue is clear.

We need to fallback to the default API server when service discovery via DoH is not available.

[alexx7311]

@privacy-advo We found the problem, we'll fix it soon.