FRITZ!Box 4020 Service - Knowledge Base
Constant restarts: Several LEDs flash
The FRITZ!Box constantly restarts. When this happens, all or several LEDs flash continuously. The FRITZ!Box user interface cannot be opened and all or individual FRITZ!Box functions do not work properly.
Important:If the FRITZ!Box occasionally restarts, proceed as described in this guide.
Simply proceed as described below. After each measure, check whether the problem persists.
1 Restarting the FRITZ!Box
- Unplug the FRITZ!Box for 5 seconds.
Note:The FRITZ!Box settings remain intact. The restart will take about 2 minutes. During this time, you cannot access the FRITZ!Box.
2 Using the correct power adapter
One of the most common causes of error is the use of an unsuitable power adapter for the FRITZ!Box:
- Use a suitable power adapter to plug in your FRITZ!Box.
3 Testing whether a USB device is interfering
The problem may be caused by a connected USB device:
- Remove all USB devices from the FRITZ!Box. If the problem no longer occurs, either a USB device or its cable is faulty, or a device consumes too much power.
- Reconnect the USB devices to the FRITZ!Box one by one to find out which device causes the problem.
- For testing purposes, use a USB hub with its own power supply (active USB hub) to connect the device causing interference to the FRITZ!Box.
- If the problem also occurs when using it with an active hub, replace the USB device.
4 Resetting the FRITZ!Box
If the problem still occurs, the FRITZ!Box is in an error state:
- Use the recovery tool to reset the FRITZ!Box.