Okay, you have to have the denonavr component installed, because I think the HEOS integration cannot turn off the device. So the problem lies in the 403 error. Do you also have _init_py, manifest.json and media_player.py in the denonavr folder? And you are sure that NR1710 is accessible through http at port 8080 and not 80: You can check at:
http://192.168.1.17:8080/goform/formMainZone_MainZoneXmlStatusLite.xml
Edit: sorry i see that port 8080 is the correct one for you
i donāt quite understand what you mean with āhave the denonavr component installedā isnāt that installed by default?
what i did now is downloaded all files from the denonavr folder: https://github.com/home-assistant/home-assistant/tree/dev/homeassistant/components/denonavr
and placed them in /config/custom_components_denonavr/denonavr
i did not edit the files. is there anyting i missed?
looks like the path is still pointing to the default HA folder. i donāt see the ācustom_componentsā anywhere.
after a restart of HA i still see this in the log:
Logger: DenonAVR
Missing status information from XML of Main for: Power, InputFuncSelect, Mute, MasterVolume
8:57:53 AM ā components/denonavr/media_player.py (ERROR) - message first occurred at 8:56:23 AM and shows up 10 times
I meant that you have to include denonavr in your configuration file. But you do that right now so that is good. I do not work with the custom component option because with my SR7011 everyhing works right out of the box.
Did you precisely follow the post of @Sand? I think you indeed place the items of https://github.com/home-assistant/home-assistant/tree/dev/homeassistant/components/denonavr into folder custom_components/denonavr. And then place in the denonavr folder init.py, denonavr.py and ssdp.py.
that is what i did.
the only part i do not understand is his comment below. (i just pasted that line into line 1 of the media_player.py)
And in media_player.py I changed the import to:
from .denonavr import denonavr
I do not use this, so I am guessing but can you change line 6 from mediaplayer.py?
It is now "import denonavr"and replace that with āfrom .denonavr import denonavrā
Maybe @Sand can help
i replaced the media_player.py again from the HA github page. now its working!!!
thank you so much for your helpā¦ i spent so much time on this!
learned alot in the process !!
A bit late to see this. But looks like you figured things out 
Had the same problem with avr-x2400H. Creating custom component helped but now in media_player.py we have to change MediaPlayerEntity to MediaPlayerDevice couse file was updated recently and main media_player file did not. Everything works fine but in logs appeared new error
Unable to get device information of host 192.168.31.111, can not use the serial number as identification 10:46:26 ā custom_components/denonavr/denonavr/denonavr.py (ERROR)
Iāve spent a couple of days trying to get the steps by @Sand working with my NR1510, kept getting the error:
Missing status information from XML of Main for: Power, InputFuncSelect, Mute, MasterVolume
Turns out that the custom_component was still defaulting to port 80 (despite setting explicitly in host) and non-2016+ AVR for some reason. Iāve ended up overriding the receiver_type setting and itās now working, but itās a non-ideal workaround obviously. In case anyone comes across this with the same issue, in denonavr.py I added the below just above the receiver type assignment (search for āSet ports and update methodā).
# Force type to AVR_X _2016
self._receiver_type = AVR_X_2016.type
This will almost definitely break any integrations with a pre-2016 receiver, so use with caution. Iāll likely come back to this at some point and try to figure out the root cause.
For reference, my configuration.yaml entry looks like:
media_player:
- platform: denonavr
name: living_room_receiver
host: marantz-nr1510.local
Thanks for this - helped me get the integration working for my Marantz NR1509