Here is a list of things you can do to troubleshoot the issue:

1. Restart your device.
2. Check if the Wi-Fi network is set to ‘hidden.’ If so, you won’t be able to connect simply by selecting the network from the available networks list.
3. If the network is configured to use MAC address filtering, make sure your MAC address is added to the list of allowed devices.
4. Check your Wi-Fi network settings in case the Wi-Fi network is using Enterprise authentication or has a certificate-based authentication such as PEAP.
5. Make sure your Wi-Fi password is correct in case you are using a password-protected network.
6. Update your device’s network drivers.
7. Move closer to the router or the source of the Wi-FI signal.
8. Check if other devices are able to connect to the same Wi-Fi network.
9. If necessary, check to see if your device is capable of connecting to the secure Wi-Fi network.