I asked google about CM400 problems and there are no shortage.
https://community.netgear.com/t5/Cable-Modems-Routers/A-few-problems-with-CM400/td-p/1289241 for example and others tell me that it's not too reliable for many.
Next you tell me about the AC2300. No surprise there as these are made, boxed up, put in a container to float across the ocean(s) as the maker works to fix the firmware. I do not expect routers to work right out of the box. Without fail I get to update the firmware, do a factory reset then set it all up. Sometimes I find that features when turned on cause a lot of issues. I won't get into that but STOCK is best. Don't get fancy and certainly ....
DO NOT HIDE THE SSIDs.
To me this reads just like the last thousand calls. Also, look at the bug fixes for December 2018's R7000 Firmware:
Fixes the issue where the router should not remember the device name that was changed before the reset.
Fixes the issue where the OpenVPN client Connection Type shows as wired in the Attached Devices page but no information about the client shows in the VPN Client Devices tables.
Fixes the issue where the user can access the Internet Setup page via the Router/AP/Bridge/Repeating mode page.
Fixes the issue where some functions are grayed out if the user is using Firefox as the web browser.
Fixes the issue where watch devices cannot be detected and don’t display on the attached devices page.
Fixes the issue where some devices will display an unknown device name.
Fixes the issue where offline devices do not disappear.
Fixes the issue where the device name will show an unknown string."
Another product that you had to wait for the fixes.
-> Since almost every router off the shelf is out of date, you can't throw money at this. You need to get a networking expert to try the usual. Get the router(s) firmware current, don't get fancy with the settings and test.
I've now wasted literally hundreds of hours trying to solve this issue. Any help would be great appreciated.
ISSUE: Devices don't reliably connect to the internet, especially after a power outtage.
DETAILS: I've noticed that if the power goes out, or if I have to reboot the router to get internet access back (once every week or two), then most every smart device in the house doesn't automatically reconnect when power comes back. I have 3 amazom echoes, 1 Google Hub, a WInk Hub, an Ecobee thermostat, 2 TPlink wifi light bulbs, 2 smart TVs, and various smart outlets.
The only solution I find is to manually reprogram every device to use the SAME wifi network it was using before the power cycle. Some reconnect eventually (after failing a few times). Some see the wifi, but can't see the internet (Google, Ecobee, my wife's Laptop). Some don't see the wifi at all or can only connect to the guest wifi (Echoes, ecobee).
The only devices that DO connect ok are my laptop (most of the time) and our iPhones (about 50% of the time... sometimes have to reboot the phones).
It is stunningly frustrating to have to reprogram every smart device in the house every single time!
WHAT I'VE TRIED:
* Rebooting and Hard Resetting the router and modem (Netgear CM400)
* Firmware updates
* Calling Xfinity for them to send a system reset.
* Replacing the Netgear R7000 router with a new TPlink AC2300 router (which amusingly didn't work out of the box until I hard reset it...and gets speeds 1/7th that of the netgear router at all distances)
I'm willing to throw any amount of $ at the problem now due to time wasted. I just need fast reliable internet that everything can connect to. Please help!