Before connecting HP device to the modem WIFI network please change the security mode option for your WIFI network on the modem GUI then restart modem for a minute after applying changes on the WIFI. Then connect the HP device to the modem 2.4 network.

Launch a web browser, such as Internet Explorer, Firefox, or Safari.  Enter http://192.168.0.1 into the address box, and press the Enter key.  The https:// Redirect page will appear.   
The Surfboard Web Manager is begin redirected to a more secure connection, click the Proceed button to continue.  The Gateway > Login page will appear.

The Username field has admin populated, enter the custom password in the Password field.

Click the Login button.  The Gateway > Summary page will appear.
The Gateway > Connection > Wi-Fi > Networks > Click on Edit 2.4 Ghz 

Click on the drop down arrow on security mode then select WPA2PSK(AES)

 Click on Save.

Then try the below steps to connect HP device to the modem 2.4 network.

1. Write down your network name (SSID) and WEP key or WPA passphrase.
2. Start Wireless Setup Wizard. From the Home screen, touch the Wireless icon, and then touch Settings. Touch WirelessSetupWizard.
3. Connect to wireless network. Select your network from the list of detected networks.
4. Follow prompts.
5. Install software.