RTC or Browser Connection Failure

When WHIP/WHEP returns success, it only indicates that the signaling exchange is complete; the media must still be established via ICE. Perform checks across six layers: security context, session, SDP, ICE, media, and cleanup.

flowchart LR
    A[HTTPS and permission] --> B[Room and participant]
    B --> C[WHIP/WHEP SDP]
    C --> D[ICE / TURN]
    D --> E[Real media]
    E --> F[Leave and resource release]

1. Browser Security Context

• The page uses valid HTTPS, and the domain matches the certificate.
• The browser has been granted camera/microphone permissions.
• There is no mixed content or device access blocked by enterprise policies.
• Check the Console, Network tab, and webrtc-internals.

2. Rooms and Members

• The Room exists and has not reached capacity.
• Participant identity, role, and heartbeat are valid.
• Publish/Subscribe targets are correct.
• No residual old sessions for the same participant exist after a page refresh.

3. WHIP/WHEP and SDP

The request/response Content-Type should be application/sdp. Confirm the following in the Offer/Answer:

• Audio/video m-lines are not unexpectedly rejected;
• Codecs have a common intersection between both parties;
• Direction matches the publish or subscribe intent;
• Fingerprint and DTLS are functioning normally;
• Candidates are not corrupted by proxies or serialization;
• Location/ETag and session IDs are saved.

4. ICE and Network

Observe the ICE gathering, checking, connected/failed states, and the selected candidate pair:

• Success on LAN, failure on WAN: Check external IP, NAT mapping, and STUN.
• Symmetric NAT failure: Deploy and verify TURN relay.
• UDP disabled failure: Provide TCP/TLS TURN.
• Multiple NICs: Remove or lower the priority of unreachable candidates.
• TURN authentication failure: Check temporary credential validity, clock synchronization, and realm.

HTTPS reverse proxies cannot forward all ICE media ports.

5. Connected but No Media

• Check if the publish track is actually sending and if the browser is muted.
• Verify if codec, resolution, bitrate, and direction are negotiated.
• Verify if the MediaServer has established the corresponding MediaSession and stream.
• Verify if the subscription topology points to the correct publisher.
• If there is video but no audio, check audio permissions, m-lines, and codecs.

6. Reconnection and Release

Media sessions should be released after the page is closed, a member leaves, or a timeout occurs. Before reconnecting, query the old session, release it based on the actual server-side identifier, and then create a new session. Continuously increasing ReleaseFailed/Unreleasable counts must trigger an alert.

Submitting Failure Evidence

Provide the browser and version, network type, Room/Member/Session IDs, sanitized summaries of Offer/Answer, ICE state, selected candidate type, MediaServer logs, and the time of failure. Do not submit long-term TURN secrets or full login credentials.

Recovery Criteria

Successfully complete publishing, subscribing, network disconnection reconnection, and leave-cleanup in both LAN and target WAN environments; multiple consecutive refreshes must not produce duplicate members or leaked sessions.