FRITZ!Box: find or change the Wi-Fi password

What the message looks like

Ein neues Gerät soll ins WLAN, aber das WLAN-Kennwort ist unbekannt oder wird abgelehnt.

Common causes

• The password was changed and not written down.
• It is mixed up with the password of the box settings.
• The device connects to the wrong network (2.4 GHz and 5 GHz often have two names).
• Typing errors: case matters, and characters such as 0 and O look alike.

Check

1. Show the saved Wi-Fi password on a Windows PC (insert the Wi-Fi name)
   netsh wlan show profile name="MyWiFi" key=clearCopy
2. Which Wi-Fi is this computer connected to?
   netsh wlan show interfacesCopy
3. Is the box reachable so you can change the password?
   ping fritz.boxCopy
4. Read the saved password on macOS (insert the Wi-Fi name, asks for login)
   security find-generic-password -wa "MyWiFi"Copy

Fix

• Check the label on the box: it shows the Wi-Fi key if it was not changed.
• A device that is already connected often still knows the password. On Windows the command netsh wlan show profile shows the key in the field Key Content.
• To change it, sign in at fritz.box and open the Wi-Fi section, security or radio network page. Menu items vary with the firmware version.
• Choose a long password with letters, digits and symbols, save, then reconnect all devices.
• Check whether the 2.4 GHz and 5 GHz networks have different names and pick the right one.

FAQ

Do I have to reconnect all devices after changing it?

Yes. Every device needs the new password, including printers, TVs and smart-home devices.

Is WPS a good alternative?

Yes, for a quick connection. The button on the box and the function on the device must be started within a short time of each other; the details depend on the model.