@Khilfiaibaq 

Hi, have you referred to the below setup video to install the router? If not yet, give it a go first:
https://www.tp-link.com/support/setup-video/

If you still failed, please refer to the troubleshooting suggestions below to check your settings:
https://www.tp-link.com/support/faq/1556/

If this still doesn't help, please show us the WAN status page on the AX1800, and tell us who is the ISP, we will confirm.