If you have a router, which uses the older WEP wireless encryption, you may not able to connect your camera to your WiFi network.
If you can, change the settings on your router to use AES encryption.
If your router doesn't give you the option to use AES, and you have to use WEP, go into your router's backend settings, and find a page called 'WLAN Setting', and look for 'WLAN Encryption'. There should be one option called '802.11 authentication', where you may see your router set to 'Open'. If this is the case, please change it to 'Share', and press save.
This should allow your cameras to connect to your WiFi network.
Note: the name for the button you need to press can differ depending on router brand, so you may need to have a look to find the right place to make this setting change.