System Time plays a gigantic role in the web interface of tplinkwifi.net to allow your router to acknowledge the duration for which your router is operated by a user. A user can also utilize the System Time feature in a much beneficial way by using it for other time-based features like Parental Control and Access Control. The duration for which other users will use the Wi-Fi connection is tracked by the System time and it also tracks the time for which other users have access to the specified websites. Make sure that the time zone your router is using in this feature is accurate according to the region.
https://tplinkwifi-net.info/how-to-update-firmware-tplinkwifi-net/
https://tplinkwifi-net.info/tplinkwifi-net-tp-link-ax11000-wifi-router-setup/
https://tplinkwifi-net.info/how-to-change-tplink-router-password/