Connection Failed Errors

General Network Checklist

Before diving into protocol-specific issues, run through these checks:

• [ ] Mac and target device are on the same network subnet (e.g., both on 192.168.1.x)
• [ ] Ethernet is being used (Wi-Fi is a common source of intermittent failures)
• [ ] macOS firewall is not blocking CueSync — check System Settings → Network → Firewall
• [ ] No VPN is active (VPNs often change routing and block LAN broadcast)
• [ ] Target device (console, node, software) is running and listening

Art-Net Connection Failed

Symptom: CueSync shows "No Response" in Art-Net output, or target console receives no DMX.

1. Verify the destination IP in CueSync matches the console's IP exactly.
2. Confirm UDP port 6454 is open — test with: nc -zuv [IP] 6454 in Terminal.
3. Try switching from unicast to broadcast (255.255.255.255) as a diagnostic step.
4. Check the console's Art-Net input is enabled and universe number matches CueSync.

sACN Connection Failed

Symptom: sACN universe shows no data on receiver.

1. Verify multicast is enabled on your network switch (some managed switches block multicast by default).
2. Try unicast mode with the receiver's IP if multicast is blocked.
3. Confirm the universe number matches exactly on both sides.
4. Check the receiver's priority settings — a higher-priority source may be overriding CueSync.

OSC Not Received

Symptom: Target application (Resolume, QLab, etc.) does not respond to CueSync OSC output.

1. Confirm OSC input is enabled in the target application's preferences.
2. Verify the port number matches — the most common mistake is a port mismatch.
3. Check the target is listening on the correct IP (some apps only listen on specific interfaces).
4. Use a free OSC monitor app (e.g., Protokol) to confirm packets are arriving.

Diagnosis Steps

If problems persist:

1. Open CueSync's Protocol Monitor for the affected protocol — confirm packets are being sent.
2. Use Wireshark on the Mac to capture network traffic and verify packets are leaving the interface.
3. Ping the target device to confirm basic IP connectivity.

Still Stuck?

Contact support with:

• CueSync version (Help → About)
• Protocol type and target application/device
• Your network topology (same machine / same switch / different subnet)
• A screenshot of your Protocol settings in CueSync