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Internet works but Windows 10 Pro sporadically says it has no connection. I have no clue why it seems to randomly do this, and sometimes restarting does not fix it. Happens on numerous networks (and ISPs).

This is presumably a failure of NCSI (Network Connectivity Status Indicator) Probing?

This prevents access to at least the Windows Store, Xbox Console Companion app (and all games there), and the Windows feedback tool. But Windows Update works. Here is a list of reported apps and features broken along with NCSI probing.

Symptoms

Taskbar

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Windows Store

Error code 0x800704CF

Xbox Console Companion

Xbox Networking settings

All menu icons in the Windows Settings under Get Help

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Windows feedback tool

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Troubleshooting steps taken

  1. Verified access* to http://www.msftncsi.com/ncsi.txt

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  1. Turned it off then on again multiple times (no resetting)

  2. Used Windows troubleshooter - it always only suggests a network reset which doesn't work (this also does a soft uninstall of the network driver)

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Network Reset

Reset method 2

Also attempted this manually using command line statements (https://www.minitool.com/news/reset-tcp-ip-windows-10.html)

Command line resetting

  1. All the steps suggested for troubleshooting networking in the Xbox app: https://beta.support.xbox.com/help/Hardware-Network/connect-network/server-connectivity-xbox-app-displays-blocked

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  1. Verified no VPN is configured

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  1. Verified no Proxy is configured

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  1. Reset IPv4 settings, toggled IPv6 settings

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  1. Toggled Active DNS Probing.

  2. Verified up-to-date through Windows Update, including the Windows Update Assistant utility (which resolved a different issue on the afflicted computer alerted as a Windows Notification "Your version of Windows 10 is out of date").

  3. Checked for viruses with a full Windows Defender scan (the only antivirus software) on the operating system's install drive.

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  1. Checked the hosts file (in its default state)

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  1. Ran the System File Checker

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  1. Removed invalid security certificates

Other similar questions

  1. Windows reporting No Internet Access when there is (and NCSI tests pass) - Disabling probing does not fix anything

  2. Windows 10 store won't connect to the internet - Different error code and limited in scope

  3. Windows 10 No Internet - Caused by a virus

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* Note that the IP resolved from the NCSI URL cannot be pinged (and this is normal, so ignore it).

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Elaskanator
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  • By network reset you mean this right? – Ramhound Apr 25 '20 at 07:07
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    "can read the file and resolve the IP but cannot ping that IP." - You are not supposed to be able to ping dns.msftncsi.com so your inability to do that doesn't indicate anything. I verified that fact on a PC that is indeed able to receive updates and connect to Xbox services. – Ramhound Apr 25 '20 at 07:09
  • @Ramhound Not sure, but the troubleshooter did a soft-uninstall of the network driver and scheduled a restart. I also tried some other command line statements to reset stuff. – Elaskanator Apr 25 '20 at 07:15
  • Have you tried to reset the router? I know you indicate you are able to connect a Surface device, but that is using the WLAN network, internal to the router. This is to rule out the router configuration. Can you try that method in the screenshot? What security software do you have installed? – Ramhound Apr 25 '20 at 07:16
  • @Ramhound I just did that. No success. I am pretty sure it is identical to the reset I did using the Windows troubleshooter as well. Installed security software is not the issue either. The Surface device is also on a router which is on the modem that I am directly connected to here (i.e. I do NOT have a router inbetween me and the modem). – Elaskanator Apr 25 '20 at 07:25
  • What about resetting the router's configuration using the push button and/or configuration page? Most routers allow you to restore the configuration. if your router does offer that option, you can try it, and see if anything changes. If nothing changes restore the configuration of the router back. – Ramhound Apr 25 '20 at 07:26
  • Everything is pointing to the router configuration. However, it appears you have a pending restart that is required. It's also possible the problem is a network driver, although, it appears you have partial connectivity (although difficult to actually determine that). – Ramhound Apr 25 '20 at 08:20
  • Default gateway is the modem's IP and it traces all the way to that Google DNS. I even tried using it as my DNS at one point. – Elaskanator Apr 25 '20 at 07:20
  • So, as I get it: DNS and ICMP work fine and only issue you have is with Windows detect network connectivity? Have you tried changing LAN cable? Sometimes it helps.

    To be honest, looks like one of system services blocked by firewall.

     – geoai777 Apr 25 '20 at 07:37
  • @p0rc0_r0ss0 - No; The author is unable to install any updates through Windows Update, Xbox Console does not work, Windows Store does not work. What isn't clear is if the author is able to go to any website within a browser. – Ramhound Apr 25 '20 at 08:15
  • In the screenshot of IPv4 configuration above, "Client for Microsoft Networks" appears to be missing. If you verify it is missing, you can add it in the Adapter Properties (Click on Install, then Protocol). You can also correct this by uninstalling the network card (Device Manager) and then installing the same or upgraded driver. – John Apr 25 '20 at 11:04
  • "Client for Microsoft Networks" was at the top of the list but I scrolled down. – Elaskanator Apr 25 '20 at 19:56
  • I can install Windows updates, it just refused to update Windows from version 1809 until I forced it yesterday. I have since restarted my computer and installed more updates so there is no pending restart, and it still thinks I have no connection even though it is clearly working. – Elaskanator Apr 25 '20 at 19:57
  • @p0rc0_r0ss0 The troublshooting steps here included verifying that Windows Firewall is not blocking system services. – Elaskanator Apr 25 '20 at 19:59
  • I haven't tried a different ethernet cable yet, but I don't have another one here, let alone one that reaches. I'm using a 50 foot cat6 cable right now. – Elaskanator Apr 25 '20 at 20:06
  • Try lower connection speed to 10MBs and see what happens – geoai777 Apr 26 '20 at 05:19
  • @p0rc0_r0ss0 That didn't work. – Elaskanator Apr 26 '20 at 19:22
  • The modem was just toggled to battery power for a moment, and even tho it didn't restart, and even though this already happened earlier while I was having the problem, it now fixed my problem. – Elaskanator Apr 26 '20 at 19:29
  • And... it's back. – Elaskanator Jun 07 '20 at 01:35
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    @Elaskanator I found a solution that worked for me, please see my answer. Also, awesome job on documenting all of your efforts, with screenshots! – David Refoua Jan 24 '21 at 21:25

2 Answers2

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In my case, I found that NCSI failing the dns.msftncsi.com test was the root cause of my problem.

After extensive tests and a lot of headaches, I found out that the recursive DNS server in my network wasn't functioning properly in time to make Windows' NCSI happy.

Solution:

Make changes to the C:\Windows\System32\drivers\etc\hosts file, and place the expected record manually so the test never fails:

131.107.255.255    dns.msftncsi.com

This will resolve the issue with the DNS check permanently, and although it will always report the correct value to the system (even if no Internet is actually available), NCSI can actually deal with this by performing additional HTTP queries to http://www.msftncsi.com/ncsi.txt and http://www.msftconnecttest.com/test.txt, which are usually used to detect captive portals.

In any case, personally, I don't care if it returns a false positive. I simply want to avoid the annoying false negatives (erroneous detection of no Internet).

Since the Spotify app and Microsoft Store both rely on this “feature” of Windows to detect network connectivity, it's best to just forgo the actual test when it's buggy and never actually works correctly.

David Refoua
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0

Try toggling the registry value for EnableActiveProbing under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internet

Ram
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