Installation of my new TP-Link Deco P9 mesh system went smoothly until I tried to connect my HP LaserJet P1102w printer to the Deco wifi network. It simply would not connect. Got messages from HP printer software indicating that printer could not connect with any available wifi device or that the SSID credentials for Deco wifi that I provided would not work. Verified credentials, uninstall and reinstalled printer software/drivers on PC, updated printer firmware, and still no joy. Lots of time and frustration!
I was about tto pack it up and send the Deco P9 system back, but decided to first try calling TP-Link Help Desk. Rep thought that HP printer might only be able to operate on 5 ghz Deco network. He said Deco system operates on 5 ghz when Deco and device (printer, in this case) are close to each other and on 2.4 ghz when they are far apart. Suggested that I turn off Deco 5 mhz signal and try configuring printer wifi connection again, then turn 5 mgz back on after connection is established. That worked perfectly.
To turn off 5 ghz signal, use Deco app. Click on array at right bottom of Overview Screen to get to Setting. Then click on wifi icon to turn off/on either 5 or 2.4 ghz signal. If the option to turn off/on does not appear, then click Update Deco on Settings page, which will install new firmware.
Thank you TP-Link Help Desk!