The error message "Authentication failed. Check whether the authentication information is correct, and try again" appears when I try to set up the Wireless LAN setting.

The error message "Authentication failed. Check whether the authentication information is correct, and try again" appears when I try to set up the Wireless LAN setting.
Use a different character according to the specification of the RADIUS server.

Examples of RADIUS server limitation:

• Windows Server 2008 R2 NPS (Network Policy Server):
  A user ID or password that contains a multibyte character.
• FREE RADIUS (Linux / Windows):
  A user ID or password that contains "\"