Since moving to 1.1.1 Build 20200716 rel.84595(5553) last summer, my AX11000 had been working well, with no issues dropping 2.4 gHz devices.  Until 3 days ago.  All of a sudden, no device (Android, MacOS, iOS) could successfully connect to the 2.4 network.  Encryption was WPA/WPA2-Personal (WPA2-PSK),  AES encryption, Smart Connect  disabled.  The only thing that would allow devices to connect was turning off encryption entirely on the 2.4 GHz band.  No amount of rebooting, or fiddling with wireless settings made a difference.  Not at all optimal

I'm considering just getting a 2.4 GHz AP from a different vendor, and hanging it off the router, hardwired, in a different room.  Life is too short to have to keep monkeying with this.

@Largeshow ... Read one of earlier posts. There is an encryption setting on the 2.4 band that many devices choose when connecting on the band. Change that setting and it should fix the issue. Feel free to look back at my posts, as I worked with support for weeks to get to the root of the issue. I .gurss you like many of us have smarthome devices and probably a good number of them like many that have posted here. Its probably not the USB but actually a large number of the devices connecting on that band over time causing router to drop them. I'll include a screen shot of what the setting should be here. Hope this helps you!

@Jerryb 

So guys I also used to have the issue with 2.4 gigahertz just disappearing and nothing being able to reconnect until I rebooted..

The issue has predominantly gone away for me and here's what I've.doene:

(1) latest official formware5, not beta

(2)  do have my 2.4 separated from the 5 gigahertz networks I'm not using the smart function.

(3) for each of the bands I narrowed the width of the signal.  I also specified a specific channel after using a Wi-Fi analyzer at the extensions of both sides of my houses and recognizing that my neighbors were perhaps overlapping with my channel.

My suspicion, and it's only that a suspicion, is that when there is some type of network collision with nearby routers operating at the same frequency / channel, I don't understand why but it seems like that causes the router itself to stop sending out the 2.4 gigahertz signal.  I have no idea why that would be since the router is just sending it out but somehow that's causing a problem I believe.

This is not a scientific explanation This is merely just what I've observed.  I probably have over 100 devices that connect over 5 GHz and 2.4 with the majority of them being 2.4.  so certainly my network if it can manage to handle this after making some adjustments others should be able to do so as well.

feel free to quote me and ask for specific setup information and I'll happy to go look and show you

@Largeshow far up thread there is a discussion of issues with usb-c generating rfi that can interfere with 2.4 ghz routers and Bluetooth devices (https://www.google.com/amp/s/www.zdnet.com/google-amp/article/usb-3-and-usb-c-devices-can-cause-problems-with-wi-fi-and-bluetooth-connections-but-theres-a-solution/).  If the usb driver isn't well shielded, you can have 2.4 dropouts.  I experienced this with a usb-c ssd, where 2.4 would become flaky shortly after plugging it in, and right itself after ejecting it.  I could mitigate the issue by using a longer cable, locating the drive further from the router.

if your external storage isn't usb-c,  then I don't know

@Jerryb Change your encryption setting to AES ONLY and not give 2.4G devices an option. When gicwn the option support found tgey use the older TKIP encryption. Here are the screen shots again from a post little earlier. You font have to broadcast your SSID.

@samadril Thanks for the reply. I only have like 12 devices max connected at any one time but I will change that setting when I get back home and see if that helps. Appreciate the help!

@MartinKnutson my external storage device just plugs into the USB-A slot but I really appreciate you taking the time to reply.