I have a Win10 device that connects to network but not Internet consistently.

I use to connect without issue 

Seems it is 2.4Ghz only Win10 device.

When I checked, it seems it was issued only IPv6 address.  IPv6 was not enabled on Deco network so I enabled. I connected to internet but then disconnected and stay disconnected.

A week ago, I tried enabling 5Ghz only on Deco but it cause issues (printer is 2.4Ghz only).  I have since reenabled both 2.4 and 5Ghz.  Printer conbects without issue but not Win10 PC.  I have rebooted network several times but no improvement.  Win10 PC says "connected/no internet".  All other device work fine. Deco shows Win10 device off line.  Not sure of next troubleshooting steps... Any thoughts?