Hello @Alsie 

Do you mean the router fails to connect to the internet or it can no longer be powered on? 

If the internet LED is orange but other LEDs are showing up correctly as per the user guide, please follow the guide to do some basic troubleshooting.

If the router can no longer be powered on, please check the below suggestions and proceed: 
1. Please be sure you are using the original power adapter, and ensure that the power button on the back has turned on.
2. You may try another power adapter with the same power specification, which is 9 V ⎓ 0.85 A.

3. Try to reset it by holding the reset button for 10s or longer to see if it will change anything.
4. Is there any power outage/bad weather before it stops working?

If nothing helps, it's suggested to contact the local tech support to be advised further:
https://www.tp-link.com/support/contact-technical-support/#Hotline-Support