Nest doorbell and outdoor camera will no longer connect to WiFi

[Non1]

We lost power a couple weeks ago and the nest doorbell will no longer connect to our WiFi since.  WiFi is fine, everything else is working no problems.  I contacted nest, they sent a new refurbished doorbell and it will not connect.  Keeps saying NC09 error code, firewall and internet error.  Both the old and new doorbell camera will not connect.  Now we have disconnected the outdoor nest camera as per a suggestion to try to connect doorbell first, but now the nest outdoor camera will also not connect to WiFi.  No changes at all with internet on our end, we even tried unplugging and rebooting it, no luck.  I don't know why this will no longer connect.  It has always worked for a few years up until 2 weeks ago.  

[cxrider]

Are you sure the error message was not NC009?    Have you googled the error message?    If the error message is NC009 have you tried these troubleshooting steps?

[Non1]

Yes sorry it was NC009.  I did follow the steps.  No luck. 

[cxrider]

No worries re: the error message.

What are you using for your Wifi device?    Is it a combo modem/router/wifi solution?    I assume other devices have no issues connecting to your wifi in the same locations as the camera and doorbell? 

[Non1]

No other issues with anything, just the nests.  Yes I it's the combo (I assume), it's just one router box everything connects to.  We tried connecting it to iPads, phones, computers, we've tried it all.   I was hoping for an easier solution than trying nest support again, as that was horrible. 

[cxrider]

Hmm..... I'm a little suprised.   I have a thermostat, five cameras, and eight smoke/CO detectors and the only time I had an issue was with one camera that is far from the AP I am using and the signal needs to go through a stucco wall, interior wall, and a floor.   It went offline after a power outage and I thought it was completely dead.   I pulled power on it for several minutes, plugged it back in, and it worked.  

When you say you disconnected the camera, I assume that means you deleted it from your account and then you tried to add it back but if fails to add again correct?

[Non1]

Yeah it's so odd. I've had power outages before no problems.  I've had the outdoor camera for a couple years, the doorbell only only year, but no problems until now.  Yes I physically took the doorbell off, unhooked it completely and deleted from the account.  And tried the new refurbished one, but both are giving the same error codes..  They go all the way to 'finishing up' after installing and then the nc009 code.  I've plugged it into computers, tried installing it without it being on the doorbell part and brought it closer to WiFi and it did the same thing.  Seemed like it was going to work then the code. I tried connecting to my hotspot on my iPhone( a suggestion I read somewhere) and same thing. Now when I was on chat with nest during this, my outdoor camera led light turned from green to red, literally while I was chatting with them.  So I called the next day regarding that camera, they sent a new cord for that camera. But they just thought it was ironic it happened while we were chatting on support but it wasn't their error.  Now I've disconnected that camera, brought it in the house,  tried the new cord, it's still red.  But it's working, recording, and live, but still led light is red.  I honestly don't know what is going on.  That's why I wondered if somehow it could be a WiFi issue as I've exhausted my nest options.  It goes all the way through the process to finishing up then fails.  

Sorry, I may not of mentioned, but the  doorbell itself is working, press the button it chimes inside and out. It's the camera part that isn't connecting on the nest doorbell. 

[cxrider]

I'm not surprised the doorbell itself works.    That is a pretty basic circuit.    The cameras will send the image data to a cloud account for your viewing.   

Do you have the ability to blacklist (blacklisting is a term for blocking) a MAC address?   Or perhaps a means of only allowing certain MACs on your wifi?     It would certainly explain the problem with the new doorbell but not the old camera unless that table dropped the MAC of your camera as well as the doorbell camera.    It would be a security option of your router software and it would probably be considered an advanced option.     Another possiblity is that your pool of available IP addresses is has been fully consumed.    Check to see if your router software limits the number of DHCP addresses available and if so, increase the number by 10 if possible.   

You might consider taking the camera to a friend's place and seeing if you can add it to their network.   If that works then you know the issue is with your home setup and not the device.

What follows below becomes technical.

Assuming that the device actually joins your wifi it would need to obtain a DHCP address.    You need to use a tool like wireshark and capture the packets on the network while one of these devices tries to join your network.    Look for DHCP packets.   You'll see DHCPREQUEST and possibly DHCPOFFER packets and maybe DHCPREJECT (I think it's reject, whatever it is it will indicate that the offered address is rejected).    If you do not see requests then the device either is not asking for an address or isn't on the wifi.   If you see requests but no offers, then the DHCP server on your router is broken in some way.   If you see requests, offers but then a rejection, it's likely that your router offered an address that the device thinks is already in use; look again to your router as the source of the problem, this time it's that the DHCP server is not properly tracking leases.

If you get this far down in the debug process then you're going to have to sniff the wifi protocol itself.   I've never had to do it and would have to research how it's done.   

Let me know what you find.   I'm curious. 

[Non1]

It looks like I can have up to 20 devices.  I only have 6 at the moment so that isn't the issue I guess. Honestly, and unfortunately I'm not computer savvy enough to understand a lot of what you suggested, but I read up through my xfinitity router info and I don't see that it's the problem here. No weird security issues, and under the limit.   I will try to bring it to another house to see if  it connects there, that's a great idea and I never thought to do that. I will have to phone a friend for the technical stuff here for them to give it a whirl. I'll just break it further with my luck.  Thank you very much for your time and all your helpful suggestions, I really appreciate it.    I will report back!

[Non1 · Accepted solution]

Finally got it fixed today.  I had to go to nest app and create a new "home" and then add my cameras to that "home" and then delete the old one. They didn't explain why there was a problem, but it has worked so far so that works for me.  The only issue is the red led light is still on my outdoor camera but it doesn't seem to be an issue. It's still recording and saving, and unfortunately it's out of warranty.  Thank you again for your help and your time!