Possible Causes:
- Network card disabled or set to static IP
- Non-Microsoft antivirus/firewall active (Kaspersky, McAfee, ESET can cause issues)
- Faulty USB-to-Ethernet adapter

Fix Steps:
1. Press F1 or click the Troubleshoot menu (top-right of the app) to check the issue list.
2. Confirm interface is connected correctly to the OBD port.
3. For G-series cars: ensure vehicle is in Diagnostic Mode → 3 quick presses of the Start button (without pressing the brake).
4. For ICOM: check PC network card is set to DHCP and confirm ICOM settings are set to DHCP in ICOM Manager.
5. For ENET: let the car sleep or disconnect the negative battery terminal for 30 seconds to reset ZGW/BDC.
6. For K+DCAN: if the cable has a switch, try a different position.
7. For K+DCAN: ensure Master is not running Ediabas 7.7 or later (7.6 is the last compatible version).
8. Restart both Car Connector apps.
9. Restart both PCs.