FRITZ!Box 6820 LTE Service - Knowledge Base

FRITZ!Box 6820 LTE Service

LAN connection to FRITZ!Box cannot be established

The LAN port cannot be used to establish a connection to the FRITZ!Box. A computer, NAS system, or other network device connected to the FRITZ!Box is not detected and cannot access the internet or the FRITZ!Box user interface. One of the following error messages may be displayed by the device:

  • "A network cable is unplugged."
  • "Network cable unplugged."
  • "You are currently not connected to any networks."

Simply proceed as described below. After each measure, check whether the problem is solved.

1 Restarting the FRITZ!Box

  1. Unplug the FRITZ!Box for 5 seconds.

    Note:The FRITZ!Box settings are retained. The restart takes about 2 minutes. During this time, you cannot access the FRITZ!Box.

2 Installing the latest FRITZ!OS

Perform the following steps on a different device connected to the FRITZ!Box:

Important:If you cannot access the FRITZ!Box with any device, proceed as described in the guide FRITZ!Box user interface cannot be opened.

  1. Install the latest FRITZ!OS on the FRITZ!Box.

3 Installing the latest software for network adapters

  1. Install the latest driver for the computer's LAN network adapter or the latest software for the device.

    Note:Often the Windows Update does not offer all of the latest device drivers. Therefore, use the drivers from the manufacturer's website (for example Intel, Broadcom, Realtek).

4 Connecting the device directly to the FRITZ!Box

Perform the following step if the device is connected by means of a hub/switch, powerline adapter, LAN/Wi-Fi converter, or other devices instead of being connected directly to the FRITZ!Box:

  1. Connect the device directly to a LAN port on the FRITZ!Box. If possible, use the yellow cable included with the FRITZ!Box.
  2. If you can now establish a LAN connection to the FRITZ!Box, the intermediary device or its cabling was causing the problem:
      1. Make sure that any intermediary devices function properly.
      2. Update the software / firmware of all intermediary devices.
      3. Use a different, short network cable to connect the devices to the FRITZ!Box.

5 Testing a different cable

The device may be connected to the FRITZ!Box by means of a network cable that is too long, incorrectly wired, or defective:

  1. Use a high-quality network cable that is as short as possible (for example the yellow cable included with the FRITZ!Box) to connect the device to the FRITZ!Box.

    Note:Any standard STP-type (Shielded Twisted Pair, 1:1) CAT5e Ethernet cable that is no longer than 100 m can be used to connect a device to the FRITZ!Box.

6 Disabling energy-saving functions for the network adapter

  1. If energy-saving functions are enabled for the computer's LAN network adapter or the device, disable them for testing purposes.

    Note:In Windows, many LAN network adapters allow you to select various energy-saving options in the Windows Device Manager. You can find these settings on the "Power Management" tab in the properties of the network adapter.

7 Adjusting the FRITZ!Box's LAN settings

Problems may occur when negotiating transmission rates. Therefore, test whether the connection can be established when you adjust the settings for the LAN port being used:

  1. Open the FRITZ!Box user interface on a different device.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Settings" tab.
  4. If "Green Mode" is enabled in the section "LAN Settings", enable "Power Mode".
    • If "Power Mode" is enabled, enable "Green Mode".
  5. Click "Apply" to save the settings.

8 Testing a different device

  1. Connect a different device to the LAN port on the FRITZ!Box.
  2. If the other device can access the FRITZ!Box and the internet, the first device is either incorrectly configured or defective.