Have you unplugged the router, then plugged it back in after a minute or two?
I'm struggling with some network issues too (not with the 3808) and I'm surprised about how many things get solved with a router "reboot"...
Yes I've experienced that as well, router power down/up was one of the first things I tried a few times, as well as unplugging everything else that had been connected to the router and plugging the 3808 directly into the modem/router to see if that would help.
No change with functionality and denon settings/status as per router were identical with regard to connectivity (Denon status: connected, same IP address), whether over ethernet, powerline adapter, or other devices connected/disconnected to/from modem/router.
