Random "no internet access" message when most internet works

Windows 10 Pro 2004 19041_1165 (but this goes back more than a year, so in earlier Windows versions as well)

Note: I usually use wifi, but switching to an ethernet connection from my laptop to the mesh router makes no difference.

From day to day, the internet icon (a globe) in my taskbar switches from "no internet access" to "internet access". If I click on the icon, for the particular wifi connection in use, it will either say "no internet, secured" or "internet, secured". (On ethernet, it just says "no internet" as the "secured" part would not apply.) Sometimes the state lasts for days, sometimes just a few hours before changing. All the while, most internet connections are working normally (Firefox, Thunderbird, etc.).

I have found two things that don't work when "no internet" is showing. The first is Lenovo Vantage, a diagnostic tool that came with my Lenovo X1 Carbon laptop. The second is downloads from the Microsoft store. I can log in to the store, search and select apps or programs, but they will not download. With both situations, I get some kind of no internet message.

At the same times I am having this issue, my wife's Dell XPS 13 almost never gets the "no internet" message. Her laptop is across the table from mine and accesses the same Deco mesh router.

I have of course tried rebooting my machine, switching in and out of airplane mode, and rebooting the router. Makes no difference. I have turned the 5 Ghz band on the router on and off, so my laptop would only use 2.4 Ghz. No change. I have tried everything suggested to me on a Lenovo forum, though none of the suggestions really seemed likely (ex: turn off IPV6). That is because the problem is so erratic and occurs on ethernet as well as wifi. Changing nothing or changing multiple things does not effect it.

I've found at least one other, old thread here with a similar title. It found a problem with MSN and a registry change that might have fixed it. But I have never used MSN and don't see the relevance of that thread to my issue.

Fwiw, here are my IP parameters as reported by Windows Settings. I should note that the parameters on my wife's Dell are virtually identical, save for the MAC address and the name/model of the wifi adapter:
SSID: RANDY-DECO
Protocol: Wi-Fi 5 (802.11ac)
Security type: WPA2-Personal
Network band: 5 GHz
Network channel: 44
Link speed (Receive/Transmit): 866/585 (Mbps)
IPv4 address: 192.168.68.107
IPv4 DNS servers: 208.67.220.220
63.142.200.162
192.168.68.1
Manufacturer: Intel Corporation
Description: Intel(R) Wireless-AC 9560 160MHz
Driver version: 22.40.0.7
Physical address (MAC): DC-nn-nn-nn-nn-nn

NetSpot on my laptop reports a strong wifi signal on 2.4 Ghz (-34 db) and on 5 Ghz (-42 Ghz). Moving my laptop to a few feet from the main router in the mesh boosts the signal strength but doesn't affect the "no internet access" message. Again, switching to ethernet makes no difference.

Any ideas? Or do I just live with it!

Samuria, thanks for the the suggestion about DNS. Do you think this could be causing my issue while at the same time, my wife's Dell has no issue using exactly the same DNS from the same LAN?

Thanks, Paul.

I closed my browser and Thunderbird. Then I disabled wifi. Finally, I flushed the dns cache. Did this twice, each time getting a success message.

It made no difference.

- - - Updated - - -

I tried restarting the laptop, but this time using an alternate user login. Both have admin rights.

After the reboot, user 2 had "internet access". All internet parameters were identical to the ones I posted below with the "no internet" message. Then I did another Restart and went back to User 1, my usual login. This time I had "internet access" message.

Is this a time for Twilight Zone music?

I'll have to try this again next time the "no internet access" suddenly appears.

Nothing random about "No Internet" declaration in mine; always this :

Since forever, through all version updates.

Always patently FALSE.

I have Ethernet only. ONE adapter.

Berton said:

I'd wonder if the Modem function in the combo Router has a problem.

True that mine is a combo. Windows always is connected to Internet, I use it heavily. It is Windows that falsely states "No Internet".
Are you thinking that the Internet-connected combo is lying about it to Windows? If that were the case, then surely Windows IN FACT would not connect to Internet.