Is ERR_NETWORK_CHANGED a problem with the website or with me?

With you, almost always. It's Chromium net error -21, and Chrome raises it when the operating system tells it the active network connection changed — your machine's IP address moved — while a request was in flight. That signal comes from your device, not the server. The tell is that it happens across every site, not one: a broken site gives you a refusal or a timeout on that site only. If a reload fixes it and it hits all sites intermittently, the connection under you is flapping.

Why does it keep coming back every few minutes?

Something is repeatedly changing your network identity. The usual culprits are a VPN client reconnecting on a timer or a kill-switch flapping, a Wi-Fi adapter with aggressive power-saving that drops and re-associates, roaming between two access points (or a router steering you between the 2.4 GHz and 5 GHz bands), and a short DHCP lease that hands you a new address on each renewal. On dual-stack networks, IPv6 privacy addresses also rotate on a schedule, which changes your source address out from under open connections.

How is this different from ERR_INTERNET_DISCONNECTED or ERR_CONNECTION_TIMED_OUT?

ERR_INTERNET_DISCONNECTED means Chrome sees no network at all — the cable's out, Wi-Fi is off. ERR_CONNECTION_TIMED_OUT means you had a network and the server never answered. ERR_NETWORK_CHANGED is the in-between case: you had a working network, and it was *replaced* by a different one mid-request, so the connection Chrome was using no longer belongs to the current network. The fix is to stabilize the connection, not to chase the server.

ERR_NETWORK_CHANGED: Your Network Changed, Not the Site

Problem

Chrome dies mid-load with a full-page error: “Your connection was interrupted. A network change was detected,” and underneath it, ERR_NETWORK_CHANGED. Sometimes a reload clears it; sometimes it comes back thirty seconds later. It’s Chromium net error -21 (you’ll also see it called “Error 21”).

Here’s the reframe that saves you an hour: this is not the site’s fault. Chrome raises ERR_NETWORK_CHANGED when the operating system notifies it that the active network connection changed — specifically, that your machine’s IP address changed — while a request was open. That notification comes from your own device. The connection Chrome was using was tied to a network that no longer exists, so it throws the request away rather than send your data over a link it can’t trust. People spend ages poking at the website, DNS, and “is it down for everyone,” when the answer is: your network moved out from under the request.

Symptoms

It happens on every site, not one — that’s the giveaway that it’s your connection, not a server.
A reload often works immediately, because by then the new network has settled.
It clusters around events: connecting or dropping a VPN, walking between Wi-Fi access points, waking the laptop from sleep, unplugging Ethernet, a phone switching from Wi-Fi to cellular.
It is not ERR_INTERNET_DISCONNECTED (no network at all) or ERR_CONNECTION_TIMED_OUT (a network that got no answer).

Top 3 Causes

A VPN or proxy toggling. A VPN client that auto-reconnects on a timer, a kill switch that cuts and restores traffic, or split-tunnel rules flipping — each one changes your default route and your source IP mid-request. If the errors line up with a VPN reconnecting, that’s your answer. This is the single most common trigger on managed laptops.
Wi-Fi flapping or roaming. A weak or contested signal makes the adapter drop and re-associate. So does power management that parks the Wi-Fi radio to save battery, roaming between two access points on the same network, and a router doing “band steering” between 2.4 GHz and 5 GHz. Each re-association can pull a fresh DHCP lease with a new IP — and a new IP is exactly what triggers -21.
IPv4/IPv6 dual-stack churn. On a dual-stack network, the browser can switch which family it uses, and IPv6 temporary (privacy) addresses rotate on a schedule by design (RFC 8981). When the source address the OS hands out changes, open connections are orphaned and Chrome reports the network as changed.

Diagnose with DechoNet

What’s My IP shows your current public IP and whether you’re coming through a VPN or proxy. Run it, then run it again a minute later: if your public IP changes between runs, your egress is genuinely moving, and that instability is what Chrome is reacting to. A stable IP across several checks points the finger at the local link (Wi-Fi/adapter) instead.
HTTP Check hits the site you were trying to reach from an external vantage point. If it loads fine from outside, the site is up and healthy and you’ve confirmed the problem is entirely on your side — stop debugging the server.

Resolution Checklist

Confirm it’s every site, not one. Every site → your network. One site → this isn’t the right guide; look at that site’s reachability instead.
Turn the VPN/proxy off completely and retest. If the errors stop, the VPN’s reconnect or kill-switch behavior is the cause — disable auto-reconnect or switch to an “always-on” mode that doesn’t flap.
Test on a wired, stable connection if you have one. No errors on Ethernet means the Wi-Fi link is the problem.
On Wi-Fi, disable the adapter’s power-saving setting, and if the network exposes separate 2.4/5 GHz SSIDs, pin the device to one to stop it roaming.
Run What’s My IP twice a minute apart. A changing public IP confirms your address is churning; take that to whatever controls it (VPN, router DHCP lease time, ISP).

When to Escalate

It happens on a stable wired connection with no VPN. Now it’s local and specific: a flaky network driver (update or roll it back), an OS power setting cycling the adapter, or a security/antivirus suite that inserts itself into the network stack and resets it. Test in a clean browser profile and, if you can, another machine on the same link to isolate device vs. network.
The whole network flaps for everyone. If several devices see it at once, it’s upstream — a failing router, a too-short DHCP lease constantly reassigning addresses, or an ISP link renegotiating. That’s a router/ISP fix, not a browser one.
You’re on cellular or moving between networks. Handoffs between Wi-Fi and mobile data legitimately change your IP; the error is expected there and clears on retry. Nothing to fix beyond staying on one network for the session.

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