Google refuses sign-in from browsers built on an embedded engine, such as Qt WebEngine (which Vodou uses), CEF, or Electron, with "This browser or app may not be secure." That's Google fingerprinting the engine, not a security problem with Vodou; other Qt WebEngine browsers hit the same wall.

How Vodou handles it

Automatically. On Google's sign-in pages only (accounts.google.com, accounts.youtube.com, and country versions like accounts.google.co.uk), Vodou presents itself as Firefox, which Google doesn't block. Everywhere else it keeps its usual identity. It holds the Firefox identity for 90 seconds after the sign-in pages were last active, so the redirects at the end of signing in don't switch it back halfway through. Signing in to Gmail and YouTube should just work.

Passkeys

On Windows, passkeys through Windows Hello work. On Linux there's no built-in authenticator behind Qt WebEngine, so a passkey there means a hardware security key.

If it still doesn't work

  • You're signed out every time you close Vodou. That's by design: cookies are memory-only. To stay signed in, add google.com (and youtube.com for YouTube) under Cookie exceptions: staying signed in.
  • Google asks for extra verification. Signing in through a VPN or proxy can trigger Google's own risk checks. That's separate from the embedded-browser block; complete the verification, or try without the VPN.
  • You still see "This browser or app may not be secure." Google may have changed how it detects browsers. Please report it, including your Vodou version (☰ → Help → About Vodou…); see How to report a bug.