@Kevin_Z 

Glad to see you are working this issue and I wish I had checked here several days ago. I do have to say I am INCREDIBLY frustrated that the FOUR times I have on live chats with an agent this weekend, not once did any of them acknowledge this is a known issue in spite of the fact that my initial contact was to get tech support on how to downgrade the firmware since I was confident the issue was a direct result of the firmware update. The first just had me change the DNS settings on the router and a day later another was directing me to do a hard reset, which is proposed without any attempt to address my concern about losing all my router config (which has been heavily customized as I have a lot of smart devices and every device in my home has a defined IP address (some of which have to be set on the router as the device doesn't support defining its own IP). 

Regarding your questions:

1. Who is your ISP, and what kind of WAN Connection Type you're using on the AX55?

Spectrum, Dallas, Texas via DOCSIS 3.0 cable model (350mbps)

2. Do you connect any EasyMesh or Onemesh extenders to the network? How many extenders? What are the models?

Note: If there are EasyMesh or Onemesh extenders in the network, please verify if the devices are connected to the AX55 wireless network or connected to the extenders' when they drop the internet.

Three OneMesh devices, two RE300 and on RE700X. All three still show up in Tether after the problem starts even though the AX55 doesn't. From an Ethernet--connected MacBook, even though I can't log into the AX55 once the problem starts (actually, even before WiFi devices start reporting no Internet connectivity), I can log into all three OneMesh extenders. 

3. Do you remember the previous stable version of firmware for AX55? Is it the previous 1.1.8 version?

Yes.

4. How about the LED status on the AX55 when the internet drops on some wireless client devices? Can you login to the web management page of the AX55 when there is no internet on the wireless clients but it still shows connected to the network?
All lights remain lit green regardless of the status of the Internet connectivity. No, I cannot log into the router admin page. However, when I try, I don't get a page-won't-load message, it just clocks. After about 10 minutes, it finally starts loading but all that ever appears is the background and the logo.

Additional information:

• The hardware version of my AX55 is version 1.6 (see below). However,  the router admin page shows that the firmware installed is for hardware version 1.0
• I did not manually pick the firmware file to load; I just had the router install the pending firmware update that I got a notification about on Tether. 
• In discovering this, I have to wonder if the issue isn't a specific problem with the firmware but that somehow the 1.0 version firmware was pushed to a 1.6 version device.
• I have checked the cable modem on my end (i.e., the operating state lights) and via Spectrum when the issue is happening and it always reports up. 
• I've checked all my cabling (cable model, router, etc.). 
• When the issue is happening, from an Ethernet-connected MacBook, I can connect to any other Ethernet-connected device via the router (e.g., my NAS). For a period of time, I can still connect to the Internet though no WiFi-connected device can. 
• The issue is gradual; it progresses (roughly) as follows:

1. Web admin portal inaccessible (tries to load but never functional)
2. No internet connectivity for WiFi devices
3. No internet connectivity for anything 

• At least as long as there is Ethernet connectivity to internet, the router is pingable from outside. I use UptimeRobot to monitor things at home and the ping monitor and even the port 21 monitor continue to report things are up until I power-cycle the router. The solid indication I have that things are down hard is when UptimeRobot monitor for my Home Assistant hub (connected to router via Ethernet) shows it is down. I see same thing if I go online and check monitor history on UptimeRobot.

  @Kevin_Z 

Thanks but no thanks. My home wifi is too critical to be your engineering team's guinea pig. Thankfully, I still had the Archer C7 that I replace with the AX55 and it is still (mostly) configured as needed to support my home network so I switched back to it last night. In a few months when y'all have something that is stable and working well, I will update the AX55 firmware and give running things on it a try again. In the meantime, any comment from them about the issue I noted where my hardware version 1.6 router shows that the latest firmware applied is for hardware version 1.0?

  @Kevin_Z 

The post by @NEatonJr is spot on. I have the same issue with version 1.0 firmware vs 1.6 hardware. Can you please acknowledge whether this would cause an issue?

Thank you,

Chuck

  @RickJamesBish  Thanks for the recommendation!  I usually shy away from routers that cost over $150 because the cheaper routers have always worked "good enough", but I can see now that that was faulty thinking!  With Father's Day coming up, maybe I should start laying strong hints on an ideal gift for Dad that could also save all our internet connectivity issues?

  @Kevin_Z 

Update for June 8:  Router has not dropped internet since I unplugged/waited/replugged the router to restore internet after router failed soon after beta firmware installed.  I wrote engineer Noah that I wondered if power cycling after firmware install was required after firmware install for the problem solution.  

I reported to engineer Noah that this beta firmware failed within 2 hours, required unplugging and plugging router to restore internet. Clients had all moved to the RE500X, but not connected to internet, router lights all green. Before I noticed internet failure, twice Tether said "login failed" to AX55, then AX55 showed as offline Cloud device shortly afterward./

 @Kevin_Z

I have the same issue as others have stated, the 1.2.2 update says that the router can not be downgraded ? why ? it seems like it would be a good ide to work out how to get back to 1.1.8 which for me worked well.

Thanks

Andrew

  @RickJamesBish Even worse, try having a tech reach out to you via email to tell you that the firmware wouldn't cause internet dropping. Anytime you make upgrades in firmware of software or hardware there are bugs. Unfortunately this one has a lot of bugs. I've never in my life heard from a technological standpoint that an update wouldn't make the router lose connectivity. That statement in itself is asinine. I have cameras that need to be running, they were crystal clear before and getting good connectivity now they're bugging out. TP LINK lets get a roll back please until you fix this bug! 

  @krystal1 I rolled back successfully minus having to factory reset the router and set it back up due to at least wifi indicator light not lighting up.  Anybody know if the beta firmware has rhe bug fixes or does it just allow for downgrade?

TPLink, any eta on actual non-beta firmware?