I did not change the settings, but the wireless connection has suddenly got unusable.

[Cause]
Modems and the wireless AirStation (master) might be unstable.

[Countermeasure 1] Turn on the modem and wireless AirStation again.

1. Unplug the power cable of the modems* from the outlet and plug it in again.
   
   
   
   * Indicates the modem with the router function/Optical Network Unit(ONU)/Customer Network Terminating Unit (CTU) provided by the line carrier.
   An internet-ready apartment has a LAN port on the wall instead of the modem,
   In such a case, follow the steps 2）
   
   
2. Unplug the power cable of the wireless AirStation from the outlet, then plug it in again.
   
   
   
   
3. Confirm that the DIAG LED is not lighting, and then if wireless connection can be established. 

[Countermeasure 2] Initialize the wireless AirStation, and set up wireless connection again.

1. If wireless connection is not established yet even after conducting countermeasure 1, initialize the wireless AirStation, and set it up again.
   
   Press and hold the [RESET] button (to initialize the settings) at the bottom of the device for about 3 seconds until the DIAG LED in the front gets lit while the wireless AirStation is powered.
   * Press it with something pointed such as a pen tip.
   
   
   
   
2. The DIAG LED blinks. Wait for a couple of minutes.
   
   
3. The DIAG LED is completely turned off when initialization gets complete.
   

Please reconnect to the AirStation.