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Knowledge document #55

The FRITZ!Box's Power LED flashes

The FRITZ!Box's Power LED flashes? ✔ Here you can find out what this means and how to solve the problem.

Your FRITZ!Box establishes a connection to the mobile network as soon as you insert your SIM card and enter the PIN in the FRITZ!Box user interface. This can take up to 2 minutes. During this time, the Power/LTE・DSL LED on the FRITZ!Box flashes and then stays lit as soon as the connection has been established.

This guide shows you how to resolve the following error:

  • The FRITZ!Box's Power/LTE・DSL LED flashes continuously and you cannot connect to the internet.

One or several of the following error messages may be displayed in the event log of the FRITZ!Box:

  • "No LTE network was found within range."
  • "Could not establish LTE connection.
    Reason: EPS_SERVICES_NOT_ALLOWED_IN_THIS_PLMN"

Important:If the FRITZ!Box does not establish a DSL connection, proceed as described in the guide Power LED of the FRITZ!Box flashes when used on a DSL line.

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

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Issue occurred after updating FRITZ!OS

Only follow the instructions in the following guide if the error occurred immediately after a FRITZ!OS update:

  1. Since updating FRITZ!OS, the FRITZ!Box's Power LED flashes

2 Checking the event log of the FRITZ!Box

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Event Log" in the "System" menu.
  3. Select "Internet Connection" from the drop-down list.
  4. If the FRITZ!Box indicates that the mobile network connection is established temporarily and drops repeatedly, follow the steps in our guide FRITZ!Box reports that the mobile network connection drops frequently.

3 Checking your SIM card

Although it may not appear to be the case, your SIM card may have been inserted incorrectly, it may be damaged, or it may be the incorrect SIM card. Therefore, check the SIM card in the FRITZ!Box:

  1. Unscrew the mobile network antenna located under the SIM card slot.
  2. Press the SIM card briefly to remove it from the SIM card slot.
  3. Check whether it is the mini-SIM (25 x 15 x 0.76 mm) SIM card you received from your mobile network provider and that the contacts are not damaged.

    Important:Do not use any micro or nano-SIM cards that have already been punched out and inserted into a SIM card tray because they can get jammed and damage the SIM slot.

    • If it is not the mini-SIM card you received from your mobile network provider or the contacts on the SIM card are damaged, contact your provider.
    • If it is the mini-SIM card you received from your mobile network provider and the contacts on it are not damaged:
    1. Insert the SIM card into the SIM card slot with the slanted edge of the card on the left and the contacts facing downwards.
    2. Push the SIM card into the SIM card slot until it clicks into place. A few millimeters of the SIM card protrude from the SIM card slot.
      Inserting the SIM card

4 Configuring the FRITZ!Box

Enabling roaming

The following step is only necessary if you are using the FRITZ!Box abroad (for example with a German SIM card in Italy) and your mobile network provider there uses a different provider's mobile network:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Click on the "Internet Connection" tab and then the "Mobile" tab.
  4. Enable the option "Permit roaming".

    ATTENTION!Enabling roaming could result in additional costs. Refer to your mobile network provider for information on roaming and possible costs.

  5. Click "Apply" to save the settings.

Selecting the frequency band

Depending on your mobile network provider, at individual locations you may need to select the frequency band in the FRITZ!Box manually:

Note:In Germany, the frequency bands 2.6 GHz, 1.8 GHz, and 800 MHz are used. Not all frequency bands are available at all locations, and not all mobile network providers support all frequency bands.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Click on the "Internet Connection" tab and then the "Mobile" tab.
  4. In the "LTE Frequency Band" section, enable the option "Manual" and disable all frequency bands except "2.6 GHz / band 7".
  5. Click "Apply" to save the settings.
  6. If the FRITZ!Box can establish a mobile network connection using the frequency band you selected:
    1. Click "Internet" and then "LTE Information".
    2. Click on the "Mobile" tab.
    3. Check which speed is displayed in the "Throughput" line.
  7. Repeat steps 2 - 6 with the frequency bands "1.8 GHz / band 3" and "800 MHz / band 20", and use the frequency band the FRITZ!Box can achieve the highest throughput with.

5 Using a different modem version

The software version for the FRITZ!Box's integrated mobile broadband modem undergoes constant development with each FRITZ!OS to ensure that it can establish optimal mobile network connections under all circumstances. In rare cases the FRITZ!Box may only be able to establish a mobile network connection with certain versions. Therefore, test the current and the previous modem version:

Using the latest FRITZ!OS

The modem version is part of FRITZ!OS. Make sure that the FRITZ!Box is using the latest FRITZ!OS and therefore the latest modem version:

  1. Manually update FRITZ!OS.

Using the previous modem version

If the problem occurs with the latest modem version (for example after updating FRITZ!OS), test the modem version of the previous FRITZ!OS:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "Reception" tab.
  4. Enable the option "Use previous software version for the integrated mobile broadband modem". If the option is not displayed, the FRITZ!Box model being used always uses the latest software version.
  5. Click "Apply setting" to save the settings.
  6. Now the FRITZ!Box enables the previous modem version and reinitializes the mobile broadband modem. Afterwards, the FRITZ!Box attempts to establish a mobile network connection again.

6 Checking the mobile network antennas

Mistakes made when connecting the mobile network antennas can often be overlooked. Therefore, check whether the mobile network antennas were correctly connected to your FRITZ!Box:

  1. Check the pin in the connector of both mobile network antennas. If the pin is bent or has broken off, there can be no contact between the antenna and the FRITZ!Box.
  2. Make sure that both of the mobile network antennas included in the package are correctly screwed onto the sockets on the FRITZ!Box.
  3. Swap the mobile network antennas connected to the two antenna sockets on the FRITZ!Box. Check whether the FRITZ!Box can then establish a radio connection.
  4. If you are using an outdoor antenna, check whether you can establish a radio connection if you use a different outdoor antenna or a different antenna cable. If you can establish a connection then, either the outdoor antenna or antenna cable is not suitable or is defective.

    Note:If you are using the FRITZ!Box in the indoor coverage area of your mobile network provider, test whether you can establish a radio connection if you use the original antennas included in the package.

7 Finding the ideal location for the FRITZ!Box

You can use the alignment aid to find the ideal location for the FRITZ!Box and the best position for the mobile network antennas:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "Reception" tab.
  4. Click the "Start Alignment Aid" button.
    • Now the current signal strength of the antennas is displayed by the LEDs on the FRITZ!Box (in five levels) and in the user interface.
  5. Select a location for the FRITZ!Box where the signal strength is as high as possible. When doing so, note the following:
    1. Position the antennas of the FRITZ!Box so that they are as perpendicular as possible (90° angle). For example, position one antenna vertically and the other horizontally.
    2. Place the FRITZ!Box as close to an outside wall as possible. If you know where your provider's mobile radio cell is located, place the FRITZ!Box by the wall facing the mobile radio cell.

      Important:If you place the FRITZ!Box in the attic or on a window sill, make sure that the permissible operating temperature of 0° to 40° Celsius is not exceeded.

    3. Select a location for the FRITZ!Box that is free from obstacles, sources of interference, and heat that is about one meter above the ground.
    4. Do not set up the FRITZ!Box in the corner of a room.

8 Connecting an outdoor antenna

If you are using the FRITZ!Box in the fringe area of the network coverage of your mobile network provider (outdoor coverage area), using mobile network antennas in your house may not be sufficient to establish a radio connection. In this case, increase the transmission and reception power of the FRITZ!Box by using an outdoor antenna on your roof or balcony, for example:

Note:Your mobile network provider can tell you whether you are using the FRITZ!Box in their indoor or outdoor coverage area.

  1. Connect an outdoor antenna to the FRITZ!Box.
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