Thanks for your come-back.
1. no proxy
2. in USA
3. no special router arrangement. Using a VerizonFios installed router.
This all worked until about two weeks ago (and had been working for months). Can't recall any network changes I've made at all actually. So I'm just trying to make sure that I've exhausted the options before sending it back to the Denon service folks.
Hmm, it's still stuck. After the reset, it only displays "Detecting"...