When you entered the setup menu, you used the remote and on-screen display, right? That's a limited way to do it- most manufacturers really prefer that their equipment gear be installed by people who know the fine details- not a value judgement by me in any way, but the menu is more complete if you use a computer and it's easier to see what's going on. Reading the manual is a miserable task and as a dealer, I fully sympathize but it needs to be done.
You'll need to find the AVR's IP address- enter it in your search bar and click Enter.
One thing I haven't seen- if you're using a separate power amp, is it set to turn on when it receives the audio signal? If so, that could be causing the lack of sound- if the signal level is too low, it will shut off. If the amp has a 12V trigger input, use that- the Yamaha has at least one 21V trigger output jack and it ALWAYS works. Your channel level issues need to be diagnosed individually, using each speaker, with each preamp output connected to each amplifier channel, one at a time.