Ik have a Marantz NR1608 with same issues. I just managed to get network control back without power cycle, by disabling and enabling network control. So it looks like something broke with latest firmware, i have version 3600-6184-6161-3085 currently installed.
By the way Heos controls works just fine…
I contacted Marantz/Denon customer support and explained the problem. they are investigating what/if they can do something. I will get feedback on that after the holidays.
i can only encourage everyone who has the problem with the “Marantz/Denon AVR mobile APP” of losing connection (same time as HA is losing connection) with the AVR to Contact customer service.
It is important to mention that the HEOS app is still working and operational. (if that is your case)
https://www.marantz.com/nl-nl/contactus/contact (you can change your country in the top right)
for the Dutch users u can call Marantz/Denon on 0402507800. (that is the number for technical support i got when i called the number on the website)
hope that this will trigger a load of new requests for them so they take it seriously.
i don’t think there is more we can do.
@TheFalcone I just called them (had to wait on the phone for 40 minutes), between the lines of what they were saying its oviously not a priority for them.
They think it might be linked to the AVR app and the HEOS app being open at the same time.
They don’t think it’s linked to a firmware update of the receiver.
I agree with what ou say: the more people call about this, the more seriosuly they will take it
Filed a support request through the Denon website…
After the november update, the API to control my Denon AVX-X1600H DAB is no longer responding. The Denon and HEOS app both still function fine. Many people use other apps (like Home Assistant) to control the Denon or Marantz receivers, which is one of the awesome features (!).
See also: denon integration broken · Issue #43670 · home-assistant/core · GitHub
Could you please confirm on the issue?
Could you investigate this issue and make this a priority?Thanks in advance for the service and the follow up.
Hope that this helps someone, but I was able to temporarily fix this problem by doing a factory reset. It will set the firmware back to the original that came on the unit. Steps that I took.
Should all know that I lost connectivity again today, seems that it only worked overnight. I’ll be trying the factory reset again and disable access to the internet to see if that fixes the issue.
Taylor, hi. If I were you, I wouldn’t bother with the factory reset: the issue seems to be with Denon’s firmware, and might only be solvable through an update from them.
In the meantime, I’ve found that doing a Restart of the AVR (with the unit on, press and hold the Standby button until “Restart” shows up on the display) is the most painless way of getting the connection to work again.
If you don’t need to be able to turn on your AVR remotely through Home-Assistant or an app, you can also set “Network Control” to “Off in Standby” instead of “Always” in the AVR setup.
With this network module is booted each time your AVR is powered on (and also turned off with the AVR) and HA will pick it up then.
Sebastian
I received a reply from the Denon service desk yesterday, about my ticket being forwarded to the Denon support engineers. It also stated I can expect a reply after new-year, so I guess it will be picked up somewhere next week or later. Won’t expect a fix this week anyways 
I was about to do this just now. Are you saying that connectivity failed even after your factory reset @masterfink Did disabling the auto update make any difference?
I’m not sure if they just forced the update anyway or if a factory reset doesn’t actually revert the firmware. Automatic updating was disabled before I performed the factory reset, and was still disabled afterwards when I restored my config. Could be that in the 30 seconds I went to restore my config they updated anyway.
Doing a hard restart everyday seems to fix the problem for around 24 hours and is much more convenient than a factory reset. If the hard restart doesn’t work I’d still recommend doing the factory reset though, as before I did that the restart wouldn’t fix my problem for some reason.
I read there was a fix for Denon in the latest Core build 2012.12.2
That fix was for the issue that the Denon AVR integration stopped working alltogether. The issue that is being discussed here is that every once in a while, the connection to the AVR is lost, which can be solved by for example power cycling the AVR.
I came across this post, which describes how you can restore the Denon stock firmware on any AVR (different button combo’s below the text): https://denon.custhelp.com/app/answers/detail/a_id/7257/~/avr-update-issue-–-june-2020
The text says:
Use the procedure below to revert the AVR’s firmware back to the initial firmware version as this will allow your AVR to reconnect to the network and then receive the current firmware version once again.
Looks like it can be done, but you need to make sure it doesn’t connect to the web before you have had the chance to disable auto-updates.
As Denon themselves state: a firmware update is not always necessary. If a roll back is possible, that would be a great stable workaround IMO.
Not to rain on your parade, but I have my doubts that a factory reset will solve anything.
We still don’t know what really causes or even triggers the issue, but from my (admittedly vague) recollection I’ve had this issue manifest sporadically for at least 2 years.
If you do decide to take the plunge, let us know.
I have my doubts too. I am also hesitating, as I am unsure the USB settings backup will include the comprehensive 30 minutes Audyssey setup. Don’t want to do that again. And once more if the rollback is not working.
In the meantime while we wait for a proper resolution to this issue, is there any way to stop the log spam at least? It tends to fill up my docker image if i leave it for too long without clearing the HA log.
I hoped to get the problem solved with the new release of HA. I’ve a Marantz SR7010 and it’s still connected after the update.
I have made the jump and restored the firmware on my Denon AVR-X1600H DAB per Denon’s post and @masterfink’s steps. Only had to reprogram my DAB radio tuner presets, but uploading USB backup went smoothly.
I can confirm this is a suitable workaround for now, for my type of receiver, with no apparent shortcomings of missing out on the new firmware! Connectivity is as it was before and no error flood.
I also have the x-1600H DAB and have auto-update or the firmware on and do not have a flooding of errors in home assistant. Lately I haven’t even had to power cycle my Denon as I haven’t lost connectivity.