Speech recognition fails with WebSocket 1006 error when browser extensions are active

[A-S-Manoj]

Description

Azure Speech SDK's WebSocket connection (wss://*.speech.microsoft.com)
fails with status code 1006 ("Unable to contact server") when certain
browser extensions are active — ad blockers, privacy extensions, or
VPN extensions that intercept WebSocket traffic.

Symptoms

• Mic activates, "Listening" state shows
• Live transcript never updates
• No errors visible without explicit canceled event logging
• Recognition silently fails

Root Cause

Confirmed via Incognito mode test (extensions disabled by default) —
interview flow works end to end with no code changes. This isolates
the issue to a browser extension intercepting the WebSocket handshake,
not application code.

Reproduction

1. Use a browser with ad blocker / privacy extension enabled
2. Start interview mode, click "I'm ready"
3. Speak after mic activates
4. Observe: no transcript, no error toast without canceled handler

Current Mitigation

• Added recognizer.canceled handler to surface Azure-side errors
  via toast instead of failing silently
• Verified working in Incognito / extension-free browser sessions

Suggested Future Fix

• Add a one-time browser compatibility check on interview page load
• Show a warning banner: "If the mic doesn't respond, try disabling
  browser extensions or use Incognito mode"
• Consider fallback to backend-proxied audio upload as documented
  alternative (see architecture notes on token security trade-offs)

Environment

• Browser: Chrome (issue), Incognito Chrome (works)
• Azure Speech region: Central India
• SDK: microsoft-cognitiveservices-speech-sdk