Can anyone help me troubleshoot this sudden WiFi outage?

Wifi
1

My home WiFi suddenly went out in the middle of work, and rebooting the modem and router didn’t fix it. My ISP says everything looks fine on their end, but all devices show “no internet.” I rely on this connection for remote work and deadlines, so I urgently need advice on what else to check or try to restore my internet access.

2

First thing, split the problem in two parts: modem side and router/WiFi side.

  1. Check modem directly
  • Take one laptop.
  • Plug it by Ethernet straight into the modem. Skip the router.
  • Power off modem for 60 seconds, then power it on.
  • Once all lights look normal, reboot the laptop.
  • Test internet.
    If no internet here, the issue is before your router, no matter what the ISP phone rep says. Ask them to check signal levels and error counts, not only “it’s online”.
  1. If modem works, check router
  • Plug the same laptop by Ethernet into your router LAN port.
  • Turn off WiFi on the laptop so you do not mix connections.
  • If Ethernet has no internet while modem had internet, your router is the problem.
  • Try a factory reset on the router using the reset pin for 10 to 15 seconds.
  • Set it up again with default SSID and password, then test.
  1. If Ethernet works but WiFi does not
  • Forget the WiFi network on one device, reconnect from scratch.
  • Check router WiFi is not in “AP isolation” or “guest” mode for all networks.
  • Try a different SSID name and a simple WPA2 password, no special characters for now.
  • Test 2.4 GHz and 5 GHz bands separately. Older devices choke on some mixed settings.
  1. Check for IP conflicts
  • On a Windows PC, run:
    ipconfig /all
    You want to see:
    IPv4 address like 192.168.x.x
    Default gateway like 192.168.x.1
    If the PC shows 169.254.x.x or no gateway, the router DHCP is broken or off. Turn DHCP on in the router config, or reset the router.
  1. Check cables and ports
    Sounds dumb, but I have lost hours to this.
  • Swap Ethernet cable between modem and router.
  • Try a different WAN port if your router has more than one.
  • Watch the link lights. No blinking means no link.
  1. Use your phone as a quick control test
  • Turn on mobile hotspot on your phone.
  • Connect your laptop to the phone hotspot.
  • If everything works there, your PC and apps are fine. The problem stays with home network gear.

  1. Look at WiFi quality in your place
    If internet works on wired but WiFi drops, you might have heavy interference or bad placement. Something like analyzing your WiFi coverage with NetSpot helps a lot. You see signal strength per room, noisy channels, dead zones, then you move the router or switch channels to a cleaner one.

  2. Quick work fallback
    Since you rely on the connection for remote work:

  • Use phone hotspot as a backup for short calls.
  • If your router supports it, add a USB 4G/5G modem as failover.
  • If the modem side fails again, keep notes with time and symptoms and push the ISP to check line noise and errors, not only “online status”.

If you post your modem model, router model, and what the lights look like on both, people here can narrow it down fast.

3

If it died suddenly in the middle of work and all devices say “no internet,” even after a modem/router reboot, I’d start looking for less-obvious stuff that the ISP “everything looks fine” script usually glosses over.

First, here’s a cleaner version of your situation for clarity / searchability:

My home WiFi suddenly stopped working in the middle of my remote work session. Rebooting both the modem and router did not restore the connection. My ISP reports that the line looks fine on their side, but every device on my network shows a “no internet” status. I rely heavily on this internet connection for remote work and need a reliable fix as soon as possible.

@techchizkid already covered the classic modem vs router vs WiFi split very well, so I won’t repeat all that. A few extra angles that often get missed:

  1. Check if it’s actually DNS, not the whole internet
  • On a device that “has no internet,” open a command prompt / terminal.
  • Try:
    • ping 8.8.8.8
    • Then: ping google.com
  • If 8.8.8.8 works but google.com fails, your connection is up but DNS is broken.
  • Quick test fix: set DNS manually on one device:
    • 8.8.8.8 and 1.1.1.1 for IPv4
  • If that magically makes everything work, change DNS in your router settings so every device benefits.
  1. Watch the modem’s event / log page
    Tech support loves to say “line looks fine” based only on whether the modem is online. That doesn’t mean it’s stable.
  • Log in to the modem (usually 192.168.100.1 for many cable modems).
  • Look for:
    • Event log / status
    • Lots of T3/T4 errors, ranging reboots, or “loss of sync” messages = bad signal or plant issues.
      If you see those in a big spike right around when your outage started, push the ISP harder. Tell them there are frequent T3/T4 timeouts and request a line test or a tech visit. Don’t just accept “we see the modem as online.”
  1. Check if something changed on your LAN (especially if you WFH)
    This is where I slightly disagree with the idea that it’s always modem vs router. I’ve seen these sudden mid-day failures be caused by:
  • A company VPN client pushing conflicting routes and killing all other traffic.
  • Security software firewall suddenly blocking all non-VPN traffic.
  • A second cheap router or AP someone plugged in that started acting as a rogue DHCP server.
    To test:
  • Take one laptop, plug in Ethernet to the router, and boot into “Safe Mode with Networking” (Windows) or temporarily disable VPN / corporate security tools.
  • If it works in that stripped-down state, something on the PC is to blame.
  • If multiple PCs started failing around the same time, check if anyone recently plugged in a new router, extender, or “smart” device near the main router.
  1. Look for a WAN IP on your router
    Log in to your router’s admin UI:
  • Check the WAN / Internet page.
  • You should see something like:
    • IP address: not 0.0.0.0
    • If it shows a real IP and you can ping 8.8.8.8 from router tools, but client devices still show “no internet,” then the router’s internal network / DHCP is likely the broken piece.
  • If WAN IP is blank or 0.0.0.0, the modem may be “stuck” on the router’s old MAC or the ISP lease.
    • Try “release / renew” or “clone MAC address” from the router WAN settings.
    • In some cases you have to power off modem for 5+ minutes so the ISP lease clears, then power on modem, wait, then router.
  1. Power and environment issues
    Boring but real:
  • Check the power strip / surge protector the modem and router are on. I’ve seen half-dead strips give “enough” power for lights but cause random drops.
  • If there was a brief power flicker right before your issue, gear can be in a weird half-borked state. Fully unplug modem and router for a solid 3 minutes, not just quick off/on.
  • Feel the modem and router: extremely hot to the touch = possible thermal shutdown or failing hardware. If you can, move them to a more open spot and test again.
  1. WiFi specifically acting weird after all this
    If wired devices do work after the above but WiFi stays useless, @techchizkid already mentioned checking bands and SSID. One addition:
  • Scan your environment for interference and channel congestion so you’re not blindly guessing. A tool like NetSpot is actually pretty solid here.
    • Install it on a laptop, walk around, and use it for analyzing and improving your WiFi coverage and channel selection.
    • If you see your network on a channel buried under 10 neighbors, switch to a quieter channel and re-test.
      This is especially relevant if your outage kind of coincided with a neighbor setting up a new router or mesh system.
  1. Short-term WFH survival plan
    Since you rely on this for remote work, treat it like a production system:
  • Use phone hotspot for critical meetings. Plug laptop in and keep video quality low to save data.
  • If you have a separate company laptop, test it on the hotspot vs home WiFi to isolate if the company config is breaking only home internet.
  • Document: time of failure, modem logs, screenshots of router WAN page, error messages. This gives you leverage when you call the ISP and when tier 1 keeps insisting “looks good here.”

If you can post back with:

  • Modem model
  • Router model
  • Whether ping to 8.8.8.8 works from any device
  • Whether the router shows a valid WAN IP
    people can usually pinpoint the culprit pretty fast.
4

Quick angle that @nachtdromer and @techchizkid didn’t drill into: what if the core line really is “fine,” but something in how your network behaves changed mid‑day?

1. Rule out “silent” ISP issues with a traceroute

On one wired device (no VPN):

  • Windows: tracert 8.8.8.8
  • macOS/Linux: traceroute 8.8.8.8

Patterns to watch:

  • Trace dies at hop 1: your router / LAN is the problem.
  • Trace dies at hop 2 (the ISP gateway) or jumps to crazy latency: their “everything looks fine” is superficial. Quote that trace when you call them.

2. Check for mid‑day config pushes or firmware changes

Routers sometimes auto‑update in the background, especially ISP‑supplied ones, and break stuff.

  • Log in to router, look for a “firmware version” or “last updated” timestamp around the outage time.
  • If it matches, disable any new “security” features that appeared, like parental controls, web filters or “safe browsing” toggles. I have seen those kill DNS outright.
  • If there is an “auto update” toggle, consider turning it off once you are stable again.

I slightly disagree with the heavy push to factory reset as an early step. If you WFH and rely on port forwards, VPNs, reserved IPs, you risk destroying a working configuration and losing an hour recreating it. Treat reset as a later step, after you have copied screenshots of all current settings.

3. Look for a rogue device that poisoned the network

Sudden failure in the middle of the day can be:

  • Someone plugged in a “WiFi extender” that is actually a router doing its own DHCP.
  • A smart device with a built‑in AP that tries to be the gateway.

Quick check:

  • In the router admin page, find “DHCP clients” or “connected devices.”
  • Look for anything odd that appeared today, or any device that shows as a “gateway” or “router.”
  • Temporarily unplug new / suspicious gear and power cycle only the main modem and router.

If you see clients getting IPs in a different subnet than usual (for example they used to be 192.168.1.x and now some are 192.168.0.x), that almost screams “second router handing out addresses.”

4. Corporate VPN & security stack conflicts

Because this died mid‑work, do a clean test with your work laptop:

  1. Disconnect VPN completely.
  2. Disable “secure DNS” / Zscaler / Cisco AnyConnect split tunnel options if present.
  3. Try a different device on the same WiFi that has no corporate software.

If only work laptop fails while a personal device on the same WiFi works, then your home network is innocent and the corporate stack pushed a bad profile. In that case:

  • Try another network like your phone hotspot.
  • If the laptop only works on the hotspot, send your IT a screenshot of routing table and VPN settings.

5. When wired is fine but WiFi feels cursed

If you get wired internet back yet WiFi still gives “no internet”:

  • Check if your SSID is set to use WPA3‑only or some exotic mixed mode. Some clients will show “connected, no internet” when they actually just botch the handshake. Try WPA2‑Personal only as a test.
  • Create a temporary test SSID on 2.4 GHz with a simple password and see if at least one device works there. If yes, your radio is healthy and the problem is encryption / compatibility, not total failure.

This is where a WiFi survey tool is worth it. NetSpot is decent for:

Pros:

  • Clear visual heatmaps, handy if you move around a lot during calls.
  • Shows which channels are crowded so you avoid fighting with five neighbor routers.
  • Lets you compare 2.4 and 5 GHz coverage in each room.

Cons:

  • It is overkill if you discover the real issue is a bad modem or DHCP failure.
  • You need to walk around and spend some time surveying, not ideal if you are in the middle of a crisis.
  • Full feature set is paywalled, so not everyone will want to invest if they just need a one‑off fix.

Use it after you get basic connectivity back, to harden your setup so the next outage is less likely or at least less disruptive.

6. Work continuity plan for next time

Since you rely on this connection:

  • Get a cheap backup path: 4G/5G hotspot or a router that supports USB modem failover.
  • Keep a short checklist printed: traceroute, router WAN IP, quick DNS change, hotspot fallback.
  • Note timestamps, screenshots of modem logs and traceroutes so when you escalate past the first support tier, you have concrete data.

If you can share screenshots of:

  • Router WAN page (with WAN IP, DNS and status)
  • A traceroute that fails
  • Modem event log around the time the outage began

it becomes much easier to say “this is 100% in your house” or “push ISP harder, they have line issues” without guesswork.