`4.12.3` broke all InterNet connections after login, the first time it was installed, until its VPN was disabled.

[RokeJulianLockhart]

Please answer the following questions for yourself before submitting an issue

• Filters were updated before reproducing an issue
• I checked the knowledge base and found no answer
• I checked to make sure that this issue has not already been filed

AdGuard version

./releases/download/v4.12.3/adguard-4.12.3.apk

Environment

• OS

  1. Details

     #!/usr/bin/env sh
     adb shell "
     	getprop | grep -E \
     		-e '^\[ro\.build\.display\.id\]:' \
     		-e '^\[ro\.build\.fingerprint\]:' \
     		-e '^\[ro\.build\.version\.sdk(_full)?\]:'
     " \
     | sed -E 's/^\[([^]]+)\]: \[([^]]*)\]$/\1: \2/' \
     | yq -P

  2. ro.build.display.id: FP5.VT2Q.C.092.20260330
     ro.build.fingerprint: Fairphone/FP5/FP5:15/AQ3A.240912.001/VT2Q:user/release-keys
     ro.build.version.sdk: 35

• Android device model

  1. Details

     #!/usr/bin/env sh
     adb shell "
     	getprop | grep -E \
     		-e '^\[ro\.product\.brand\]:' \
     		-e '^\[ro\.build\.product\]:'
     " \
     | sed -E 's/^\[([^]]+)\]: \[([^]]*)\]$/\1: \2/' \
     | yq -P

  2. ro.product.brand: Fairphone
     ro.build.product: FP5

HTTPS filtering

• yes, I do

Root access

• yes, I have it

Integration with AdGuard VPN

• yes, I do

Routing mode

Local VPN

Ad Blocking

AdGuard Base filter, AdGuard Mobile Ads filter

Privacy

AdGuard Tracking Protection filter

Social

AdGuard Social Media filter

Annoyances

AdGuard Cookie Notices filter, AdGuard Popups filter, AdGuard Mobile App Banners filter, AdGuard Other Annoyances filter, AdGuard Widgets filter

Security

Online Malicious URL Blocklist

Language-specific

AdGuard Russian filter, AdGuard Japanese filter

Other

No response

Which DNS server do you use?

Automatic DNS

DNS protocol

I do not know.

Custom DNS

It should equivalate the undermentioned:

1. Details

   #!/usr/bin/env sh
   resolvectl

2. Current DNS Server: fe80::a2b5:3cff:fed0:390c
          DNS Servers: 192.168.1.1 fdce:b268:c9db::1 fe80::a2b5:3cff:fed0:390c
           DNS Domain: lan

Essentially, they're not custom. Instead, they're the ISP values that are provided by my gateway.

To demonstrate:

What Stealth Mode options do you have enabled?

No response

Issue Details

1. After installing the application, via the standard package installer, invoked by Obtainium.

2. AdGuard commenced account login.

3. I attempted to generate an account entrant, via my FlorisBoard's Bitwarden integration.

Expected Behavior

Bitwarden should have operated.

Actual Behavior

It failed to connect, until I disabled the VPN (then, re-enabled it).

Screenshots

Additional Information

Had I been able to reproduce this, I would provide Bitwarden Flight Recorder logs, and PCAP. Unfortunately, I neglected to even capture logcat's output. However, I've:

Stacktrace:
java.net.ConnectException: Failed to connect to identity.bitwarden.com/[2a04:4e42:4c::347]:443
	d02.i(r8-map-id-55262569c521ac8d4f0505cb16fb7222d318dcda1292d9523b5269887d3d64b3:134)
	d02.d(r8-map-id-55262569c521ac8d4f0505cb16fb7222d318dcda1292d9523b5269887d3d64b3:26)
	td3.a(r8-map-id-55262569c521ac8d4f0505cb16fb7222d318dcda1292d9523b5269887d3d64b3:3)
	q9.a(r8-map-id-55262569c521ac8d4f0505cb16fb7222d318dcda1292d9523b5269887d3d64b3:67)
	q9.run(r8-map-id-55262569c521ac8d4f0505cb16fb7222d318dcda1292d9523b5269887d3d64b3:204)
	java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1154)
	java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:652)
	java.lang.Thread.run(Thread.java:1564)

Version: 2026.4.2 (21562)
Device: 📱 Fairphone FP5 🤖 15@35 📦 prod
CI: 🧱 commit: bitwarden/android/release/hotfix-v2026.4.1-bwpm@2e88a418a11a042fed230a0871cdcaa9bbff0c04
💻 build source: bitwarden/android/actions/runs/25866701011/attempts/1

[Swen90]

Good day @RokeJulianLockhart
Unfortunately I was not able to reproduce this issue on my side. Let's break this issue down. It looks like the only hard evidence here is the Bitwarden stacktrace:
java.net.ConnectException: Failed to connect to identity.bitwarden.com/[2a04:4e42:4c::347]:443

That suggests DNS resolution itself likely succeeded, but the connection to the resolved IPv6 address failed at the network path level. Since the issue disappeared after disabling and re-enabling AdGuard protection, this looks more like a temporary Local VPN tunnel / IPv6 routing initialization problem on first start than a filtering-rule issue.

If this issue is reproducible, please try to collect:

• logcat right at the moment of failure
• AdGuard app logs/export
• Bitwarden Flight Recorder logs
• PCAP, if possible

Here's what we need you to do:

1. Enable debug logging:
   Settings -> General -> Advanced -> Logging level -> Debug.
2. Reproduce the problem, then remember the exact time when it happened.
3. Collect logs:
   Settings -> General -> Advanced -> Export logs and system info.
4. Send this file to qa@adguard.com:
   • include [android] keyword and 6097 as an issue number in the subject of your email
   • specify the exact time when the issue occurred

Useful narrowing checks if it recurs:

• disable/enable AdGuard protection again and confirm whether it immediately recovers
• switch DNS from Automatic to a fixed public DNS and retest
• test on another network, ideally one without IPv6, or temporarily disable IPv6 on the current network if possible