I cannot connect to an access point in the Client mode.

Try taking the following measures, in this order:
-Properly select the access point’s SSID on this unit.
-Properly input the access point’s password on this unit.
-Change the wireless channel on the wireless LAN router (access point) and reconnect.
-Turn the power of this unit and the wireless device off then back on, then reconnect.
*For information on the wireless LAN router or products of other manufacturers, see the respective devices’ operating instructions.