@Ayukawa 

Few things you should check with this.

1. Make sure you have it set up as described in the following link - https://www.tp-link.com/us/support/faq/4340/

2. Make sure you have the most up to date firmware by going to http://tplinkdeco.net/ - Once your logged in click on - Advance then systems. Next click on Firmware upgrade followed by "Check for Upgrades"

If none of the above helps please open a support ticket using the directions below

1. Email support at support.usa@tp-link.com.
2. Include the model number of your Deco router, as well as the hardware and firmware versions.
3. Describe the issues you are facing and send the email.
4. Within a few minutes, you will receive an automated response with a TKID number.
5. Upon receiving this email, please access the Deco web UI by entering "tplinkdeco.net" in your browser. Navigate to Advanced > System > System Log, select "ALL" in the log type, and save the file to your local computer. Then, reply to the email you just received, attach the log file, and kindly request that your ticket be escalated to a senior engineer for further assistance.