Hi, below are some suggestions. 

 Please use the original power adapter first; then ensure that the power button on the back has turned on.

Meanwhile, it is suggested to reset it by holding the reset button for 10s to reset it.

Is there any power outage/bad weather before it stops working?

Besides, you can contact the online tech support to get some help also.

https://www.tp-link.com/en/support/contact-technical-support/#Hotline-Support

May it help.