Please confirm the following:

1. Check if the D-Link Wi-Fi app is up to date. If not, please download the latest version.

2. Check if your mobile device's Wi-Fi is on and connected. If this is your first time installing this D-Link device, please refer to the documentation included in the product packaging.

3. Try turning off cellular data for Android devices and try again.

4. Ensure that your product is supported by D-Link Wi-Fi.