Hi there, did you solve your problem. Same issue here.

Ok, so thinking about it.. I did make a "Family Profile" for my daughter's phone to see what that was like - I only added her phone and tablet to it, nothing to do with these devices that can't talk to each other. It has a schedule on it that is supposed to stop internet access at bed time and these other features that never really seemed to work right so I just stopped using the profile and removed it.... This got me thinking that maybe there is some kind of configuration remnant left behind after deleting/removing... something that was wreaking havoc on my network...

I started running some continuous pings to some devices.... I reloaded the error pro and for just a few intervals at start up I was able to ping my devices. The plot thickens, this new bit of information fuels my suspicion that some configuration remnant that I can't see because... advanced features?...  is to blame.

Quickly I create a profile "default" and add all 46 devices to it. I pause the profile and then enable it.... the next few pings fail. Dejected I turn to my phone to dig further into the app when in the corner of my eye it's brighter that it was a moment ago... there's more white against my black background, my pings are echoed back?! It's working?! Was it really the fix? I try another address quickly as if I'm racing against some unseen force coming to steal away my packets. Success! Another, also successful.

Ok, so I don't really want to add a device to this profile every time I onboard something new... can I remove it now and delete it? will everyone still like each other? Slowly, taking special care not to spook the newly domesticated packets I begin removing each device one by one from the profile, the idea here not to leave anything behind with the nuclear option of deleting the profile. With the number of devices left assigned to the profile at 0, it was time to say goodbye. So I deleted the "default" profile scattering its data to the ether with a confirmed "yes."

Sitting back at the create your first profile screen I knew what I had to do. Pausing briefly from typing this I had to switch over to the continuous ping that was still running in the background and make sure that my connectivity was still there. A knot grew in the pit of my stomach, what if this wasn't the fix? What if this $315 hunk of absolute garbage was somehow that much trashier still.... It was time to find out...

It's still there! It's still working I thought to myself amazed and bewildered. I immediately thought of the surprised Airman Doughtery from WarGames after surviving Joshua's simulated nuclear missile strike from the USSR, "Yeah, we're here! Jesus H. Christ! We're still here!"

So, I guess the moral of this story is, don't use Family Profiles. They're half baked and can really jack up your network. If you're having some flaky problems after having created one of these god forsaken things try my steps above, maybe you'll have a positive outcome. Me, I'm moving to an Orbi deployment ASAP. I don't like walking away from something I spent this much money on, but at the end of the day it can't be a guessing game of if the network is going to work or not.

Deuces eero, I'm out. See ya never.

Nope, no double NAT. Wired is just a dumb switch with PoE. All the devices get DHCP from Eero. It's just a terrible product. It was a very strange issue. I'm not sure what mechanism the profiles use, the inability to communicate makes me think it might be some type of vlan mechanism. Anyway, if someone was having some strange issue, it's a troubleshooting step they could try.

Sorry if this thread is no longer active, but I am new to Eero and experiencing this exact problem.  The OSX device is on the network and has internet access.  Eero shows the OSX device with 2 IPv4 addresses and an IPv6 address.  BUT when I execute an arp -a command from a Windows 10 machine, the IP address of the Mac is not shown in the arp cache.  And of course this means ping to that IP fails as well as attempting to telnet into the machine. Ping to the IPv6 address also fails with destination host unreachable.

The firewall on the OSX device is disabled. 

What setting on my Eero network is preventing my Windows 10 machine from seeing the iMac?