@Saran-joel_1. 

When the issue happens the first thing you want to do is to look at the LED lights to see if they are different from when it does work.

Look at the TP-Link internet LED. If that turns amber then it is losing internet from the modem. You could try to swap the cable from the router to the modem to see if that helps.

Check the firmware for your region to make sure you are running the later for your hardware version.

What you can also try is to wire your computer directly into the modem and perform the same tasks/work to see if the issue still happens.

@Tony 

well the thing is it is(led light) not  turning into ember colour, it is like green and the modem is working fine.

SO is there any problem in my router should i change it ?

@Saran-joel_1. 

Please reach out to your local support team here: https://www.tp-link.com/in/support/contact-technical-support/#Hotline-Support

They will be able to help determine the status of your router.