Hello @RajatJain ,

Welcome to our community.

May I know what the model number of your device is? Please refer to

How to find the model number of your TP-Link device 

How to find the hardware version on a TP-Link device

If you receive a "No Host Connection" or "No Main Network Connection" error during the extender setup, try these steps: 
    1. Confirm that you have entered the correct wireless password for your router. 
    2. Reset the extender and go through the setup process again. 
    3. Disable Band Steering or Smart Connect on your router and set its 5G wireless channel to Band 1 (channels 36, 40, 44, or 48). If you need help with this, check out this link or contact your router support: Changing Channel and Channel Width on a TP-Link Router.