D-Link DWA-121 User Manual page 40

Section 4 - Wireless Security
3. Enter the same security key or passphrase that is on your router and click
Connect.
It may take 20-30 seconds to connect to the wireless network. If the connection
fails, please verify that the security settings are correct. The key or passphrase
must be exactly the same as on the wireless router.
D-Link DWA-121 User Manual 40