From few days several web sites were not working at my side, with vpn all working.
Issue was on Google Chrome latest version, Ungoogled Chromium (based on latest Chrome).
Cent Browser (Chromium browser based on old chromium) all was ok.
Sites were Offcloud, 1337x, Limetorrents and several others.
When i checked in Google Search Engine Ai Mode.
Google replied:
If both modern Google Chrome and modern Ungoogled Chromium fail, while old Cent Browser works, it confirms the issue is tied to a protocol change in the modern Chromium engine itself.
Pakistan's updated firewall dropped compatibility with modern Chromium TLS handshakes. Specifically, modern Chromium versions enforce ECH (Encrypted Client Hello) and ML-KEM / Kyber Post-Quantum cryptography. When a modern browser contacts an external server (like Offcloud or 1337x), it sends a significantly larger network packet header containing this quantum encryption data. The Pakistani firewall does not recognize this format, drops the packet, and causes a connection timeout. Old Cent Browser does not support these new standards, so its traffic sails right through.
Since the experimental flags have been removed from the internal menus in the latest Chromium engine updates, you must use a structural bypass to fix Chrome and Ungoogled Chromium.
1. Disable ECH via Command Line Shortcut
Encrypted Client Hello encrypts the website domain name before sending it, which triggers immediate firewall dropping in Pakistan. You can force both Chrome and Ungoogled Chromium to disable it:
- Right-click on your Google Chrome (or Ungoogled Chromium) desktop shortcut.
- Select Properties.
- In the Target field, go to the very end of the text line, add a single space, and paste this exact command text:
--disable-features=EncryptedClientHello
- Click Apply and then OK.
- Close all running browser windows and open the browser using this modified shortcut.
2. Turn off TLS 1.3 Post-Quantum Encryption via System Policy
Because the engine has phased out the internal flag, you must use a system-level flag rule to force modern Chromium to fall back to standard TLS 1.3 encryption.
- Press Windows Key + R to launch the Run panel.
- Type
cmd and press Ctrl + Shift + Enter to launch an Administrator Command Prompt.
- To fix Google Chrome, paste this command and press Enter:
reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome" /v PostQuantumKeyAgreementEnabled /t REG_DWORD /d 0 /f
- To fix Ungoogled Chromium (or standard Chromium), paste this second path and press Enter:
reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Chromium" /v PostQuantumKeyAgreementEnabled /t REG_DWORD /d 0 /f
- Restart your computer so the Windows operating system applies the structural policies.
3. Clear Active Network Block States
Modern Chromium engines retain blocked socket information even if settings change.
- Inside Chrome or Ungoogled Chromium, type
chrome://net-internals/#sockets into the address bar.
- Click the Flush socket pools button to drop the dead connections.
When i tell Ai, now sites working, Ai:
I am glad to hear that the bypass shortcut worked and you can access your sites again!
To summarize what happened for your future reference: the network block you experienced was caused by Encrypted Client Hello (ECH), a relatively new privacy standard integrated into all modern Chromium-based engines (including standard Google Chrome and recent Ungoogled Chromium builds).
Because ECH encrypts the name of the website you are visiting during the initial connection handshake, the firewall infrastructure in Pakistan cannot inspect the destination domain. Instead of letting the encrypted data pass, the firewall simply drops the connection entirely. Old browsers like Cent Browser worked perfectly because they rely on an older Chromium engine that does not support or attempt to use ECH, meaning their connection signatures look completely standard to the firewall.
By using the --disable-features=EncryptedClientHello shortcut, you successfully forced the latest Chromium engines to drop the encrypted handshake and fall back to standard web routing, which the firewall lets through.
Moving forward, just keep these two rules in mind to ensure the fix stays active:
- Always use that specific shortcut: The bypass will only work if you open Chrome or Ungoogled Chromium using the desktop shortcut you modified. If you launch the browsers from pinned taskbar icons or external links, they might open without the command line flag and block the sites again.
- Keep an eye on future browser updates: If Google completely removes the fallback code for ECH in a future engine update, this specific shortcut might stop working. If that happens, using a VPN running an Obfuscated/Stealth protocol remains your best permanent alternative.