1. Make sure that the signal LED or any one of the 2.4/5G LED is solid on, as shown in the following figure. If not, please reset the extender and set up it again. For instructions of factory resetting, refer to the Quick Installation Guide of the extender.
2. Check whether the Wi-Fi name (SSID) of the extender is the same as your router. (How to check?)
For further help or technical support, please visit https://www.tp-link.com/support.