I have a Denon X-3400H unit that that I cannot get connected to the "main" wireless network. And I'm not alone as someone else reported something similar with a Denon receiver on AVSForum.

If I attempt to manually enter the password on the receiver and join the wifi network, the receiver fails to connect and reports the password is incorrect. Obviously, I typed the password correctly. In terms of the password, I've tried 12 characters (all lower-case), 8 characters, and even 88888888 and 12345678. In the majority* of cases, wifi setup fails with "Password is incorrect".

If I attempt to join using Airplay, iOS reports an unexpected error occurred and the receiver reports the connection failed.

The odd thing is, that it will connect to the eero guest wifi network. Yes, even with the same password as the main wifi.

And of course, I can connect successfully with a hardwire.

==Tests Performed==

I started fresh with a fw reset of the receiver and a reboot of the Eero network. After each test, I performed a network reset on the receiver.

Since I assumed that the issue was the password (being 12 characters all lower-case), I started tests with that assumption:

1. FAIL: The receiver cannot connect to main network by manually entering the password. Receiver reports "Password is incorrect."

2. FAIL: The receiver cannot connect to the main network by using Airplay.

3. SUCCESS: I configured my guest network to use a 11 character password (different password from main). The receiver connected via Airplay.

4. SUCCESS: I configured my guest network to use a 12 character password (added one letter; different password from main). The receiver connected via Airplay.

5. SUCCESS: I configured my guest network to use the same 12 character password as my main network. The receiver connected via Airplay.

6. FAIL: retest of #1 and #2. The receiver can’t connect to the main network.

7. FAIL: I configured my main network to use a 8 character password (trimmed off the last 4 characters). The receiver can’t connect to the main network using Airplay. Likewise, manual password entering encounters the “Password is incorrect.” Error.

*8. PARTIAL SUCCESS: I configured my main network to use a password of 88888888 (eero requires a minimum of eight digits/characters). The receiver connected via Airplay. However, I could not get this to consistently work (e.g, if I removed the network and attempted to re-add it, it would fail).

One other thing – when I do a manual scan of the wireless networks, Denon reports multiple instances of my wifi networks (between 4-6 instances). I’m not sure why that is.

I don't believe the receiver has a defective wireless component. Given that the receiver can connect flawlessly to the guest network, there must be some difference between the configuration of the main network vs. guest network, but given the limited app settings, I can't figure it out.

I have a support case open with Denon as well, but they just want me to do firmware resets and ship the unit it in for repair (I don't believe this is a defective wireless chip in the receiver; I firmly believe this is a software issue either with Denon or Eero or both). 

Has anyone else run into this?