majorwiki/05-troubleshooting/iphone-mirroring-connecting-hang-awdl-stall-beta.md

title	domain	category	tags	status	created	updated
iPhone Mirroring Hangs on 'Connecting…' — AWDL Data Stall (27.0 Beta)	troubleshooting	macos	macos iphone-mirroring continuity awdl rapport quic tailscale mullvad beta	published	2026-06-09	2026-06-09

iPhone Mirroring Hangs on 'Connecting…' — AWDL Data Stall (27.0 Beta)

Symptom

iPhone Mirroring on the Mac sits on "Connecting…" forever and never shows the iPhone screen.

• Mac: macOS 27.0 dev beta (build 26A5353q), MajorAir
• iPhone: Major16Pro / iPhone17,1, iOS 27.0 dev beta, same Apple ID (maj.linux@gmail.com)

Root cause (conclusion)

A bug in the iPhone Mirroring beta (both devices on the .0 developer seeds). The connection authenticates, the AWDL peer-to-peer link comes up, the TLS handshake starts — then bidirectional data stalls ~2 seconds in and the link is torn down. Deterministic, reproduces every attempt. Nothing in the local configuration was wrong. Filed via Feedback Assistant; expected to clear in a future seed.

Two real but secondary network-layer issues were found and fixed along the way (see below) — they can block mirroring independently, but were not the cause of the final 2-second stall.

The smoking gun (unified log)

Per connection attempt the sequence is always:

rapportd: Session start … linkType "AWDL", error "NoError"      # link negotiated OK
iPhone Mirroring: Installing verify block for 1 authorized peer key(s)
boringssl: TLS client read_server_hello                          # iPhone DID respond
quic: path over awdl0 received event established / promoted to primary
nw_flow_connected: Transport protocol connected (socket)
… flow:connect_stalled @2.003s                                  # stalls exactly ~2s in
quic_conn_log_summary: Connection attempts: 6, RETRY received: no, PTOs: 5   # packets sent, zero ACKs
[C1.1.1 … awdl0 … failed socket-flow (unsatisfied (No network route))]      # link dropped (symptom, not cause)

The connection is pinned to AWDL (allowed subtypes: wifi_awdl, prohibit fallback), so once the AWDL data path stalls there is no fallback and it fails. "No network route" is the result of the teardown, not the trigger. The trigger is that after the initial handshake packets, sustained QUIC traffic over AWDL gets no ACKs (PTOs).

Investigation path (what was ruled out)

• Discovery / proximity — healthy throughout. BLE + Bonjour resolve the iPhone; rapportd sees it with good RSSI, same iCloud (DF < MyiCloud >), WiFiP2P.
• Tailscale (full-tunnel) — with Tailscale connected, the attempt died at "No network route" before even reaching AWDL. Cause: RouteAll: true (accept-routes / a ::/0 advertised route) installs IPv6 default routes via utun (default → fe80::%utun0..3) that black-hole the IPv6 path AWDL needs. tailscale down is NOT enough — it only sets WantRunning=false; the macOS VPN configuration (scutil --nc list showed it still Connected) and the system extension keep reasserting the routes across reboots. Must disable in System Settings → VPN.
• Mullvad — mullvad-daemon running; "Local network sharing" was set to block, which blocks LAN/AWDL/multicast. Changed to allow (mullvad lan set allow). Kill-switch was off.
• macOS firewall — off. No Little Snitch/LuLu app installed.
• Lockdown Mode — off (iPhone).
• OS-version mismatch — ruled out; both Mac and iPhone on 27.0 dev beta.
• Device trust / re-pairing — there is no local pairing record on the Mac to reset. rapportd lists the iPhone as "PairedSys Conjectured" = trust is derived from the shared Apple ID, not a manual pairing. Forgetting the Mac on the iPhone does not force re-setup; the Mac just re-derives the association from iCloud and reconnects. (App containers ~/Library/Containers/com.apple.ScreenContinuity and the rapport stores held no device record; the "1 authorized peer key" lives in the protected system keychain.)
• Reboots / airplane-mode toggle / Mac-side AWDL + rapportd reset — no change.

Secondary issues found & fixed (do these regardless)

1. Mullvad — set Local network sharing = allow (done). Required for any LAN/AWDL feature.
2. Tailscale — do not run full-tunnel / accept a ::/0 route while mirroring; it installs IPv6 default routes via utun that kill the local link. Toggle the VPN off in System Settings (not just tailscale down) if it ever needs to be fully out of the path.
3. Orphaned Little Snitch network extension — the app was uninstalled but its at.obdev.littlesnitch.networkextension is still [activated enabled] (systemextensionsctl list). Remove via System Settings → General → Login Items & Extensions → Network Extensions. A zombie filter extension with no app behind it can black-hole traffic.

Status / next steps

• No user-side fix. Filed in Feedback Assistant.
• Debug capture saved: ~/Desktop/iPhoneMirroring-debug-20260609-0026.txt (summary + log narrative). For a full report, trigger a sysdiagnose (⌃⌥⇧⌘ + .) right after reproducing and attach it.
• VPNs restored after session: Tailscale back up; Mullvad left disconnected with LAN sharing = allow.

Useful diagnostic commands (for next time)

# Connection narrative
log show --last 10m --style compact --predicate \
  '(subsystem == "com.apple.MediaContinuityKit") OR (process == "iPhone Mirroring")' | tail -60
# rapport / AWDL negotiation
log show --last 5m --style compact --predicate 'process == "rapportd"' | grep -iE "AWDL|Pair|Session"
# VPN config really on? (CLI "down" lies)
scutil --nc list ; scutil --nc status "Tailscale"
# IPv6 default routes hijacked by utun?
netstat -rn -f inet6 | awk '$1=="default"{print}'
# Active system extensions (filters/VPNs)
systemextensionsctl list
# Mullvad LAN sharing
mullvad lan get

Related

• macos-mirrored-notification-alert-loop.md (other Continuity issue)
• Hosts/VPN context: MajorTwin project doc (Tailscale tailnet, 100.x addresses)