Is your 2.4GHz WiFi network within range?
To connect the dongle to your WiFi network, the dongle must be within range of your WiFi network. Your (default) 2.4GHz WiFi signal must also be enabled. Have you disabled this signal and is only the 5GHz signal enabled on the router?
Then follow the links below to re-enable the 2.4GHz WiFi signal.
1. Open the TP-Link Tether app and log in with your ‘TP-Link ID’
2. Select your router
3. Click on ‘Tools’ at the bottom right and then on ‘Wireless’
4. The check mark behind 2.4GHz must be checked
5. Click on ‘Save’ at the top right
Your router is not listed?
Then contact your internet provider, who can help you turn on your 2.4GHz signal.