When there is no internet connection, work from the outside in: confirm the ISP link is up, power-cycle the modem and router, then test a single wired device. If that device still has no traffic, the fault sits with your ISP, the modem, or the router configuration, not the client PC.
Symptoms
- Wi-Fi shows as connected, but browsers return DNS_PROBE_FINISHED or timeout errors.
- The router's WAN or internet light is off, red, or flashing amber.
- Only some devices lose access; others on the same network work normally.
- Speed tests fail to start or stall at 0 Mbps even over Ethernet.
- Windows reports "No internet, secured"; macOS shows a self-assigned IP address.
Common Causes
ISP outage or line fault
The provider's upstream link, DSLAM, or fibre node is down. Nothing on your side will restore service until the carrier repairs it.
Modem or router in a bad state
After days of uptime, NAT tables, DHCP leases, or the PPPoE session can hang. The device shows power but stops forwarding traffic.
Broken DHCP or DNS
The client cannot obtain a valid IP address, or it has one but cannot resolve hostnames. Symptoms differ: no IP means total failure; bad DNS means IPs work but names don't.
Cabling and physical layer
A crimped Ethernet lead, an unseated fibre SFP, or a coax splitter degrades the link. Intermittent link lights are the giveaway.
Wi-Fi radio problem
Channel congestion, a stuck 5 GHz radio, or a driver fault on the client prevents association even when the router itself is fine.
Step-by-Step Fix
- Confirm whether the outage is yours or the ISP's
Load the ISP status page on mobile data and check regional outage trackers. Call the technical hotline and ask whether your line shows sync. If the ISP confirms an incident, stop troubleshooting locally and wait for restoration. - Power-cycle the modem, then the router, in order
Unplug the modem and router from mains power. Wait 60 seconds so capacitors drain and the ISP session ages out. Power the modem first and wait for a solid online light, then power the router. Boot order matters: the router needs a live WAN to negotiate correctly. - Test with a wired laptop directly on the router
Bypass Wi-Fi entirely. Plug a laptop into a LAN port with a known-good Ethernet cable. If this device gets internet, the fault is on your wireless side. If it still fails, the problem is the router, modem, or line. - Check IP configuration and DNS resolution
On Windows run ipconfig /all; on macOS check System Settings, Network. A 169.254.x.x address means DHCP failed. If you have a normal IP, run ping 1.1.1.1 then ping google.com. Reply from the IP but not the name points squarely at DNS. - Inspect cables, ports, and link lights
Reseat every RJ-45 connector until you feel the clip click. Swap the WAN cable between modem and router for a spare. Look at the port LEDs: no light on a live port means a dead cable, a dead port, or a disabled interface. - Reset the network stack on the client
On Windows, open an elevated command prompt and run netsh winsock reset, netsh int ip reset, ipconfig /flushdns, then reboot. On macOS, remove the interface in Network settings and add it back. This clears corrupted sockets, stale routes, and cached DNS entries. - Update or roll back the router firmware
Log into the router (the gateway address shown by ipconfig, often 192.168.0.1 or 192.168.1.1). Check the vendor page for a newer firmware image. If problems started right after an update, roll back to the previous version rather than forcing a newer one. - Factory-reset the router as a last local step
Hold the reset pin for 30 seconds until all LEDs flash. Reconfigure the WAN with the ISP credentials (PPPoE username, VLAN tag, or DHCP as required). If a fresh configuration still cannot reach the internet, the fault is the modem, ONT, or ISP line and needs a technician.
Symptom to likely cause and first action
| Symptom | Likely cause | First action |
|---|---|---|
| WAN light off or red | No signal from ISP | Check ISP status, then reseat WAN cable |
| Got IP 169.254.x.x | DHCP failed | Restart router, renew lease with ipconfig /renew |
| Ping 1.1.1.1 works, names fail | DNS broken | Set 1.1.1.1 or 9.9.9.9 on the adapter |
| Wired works, Wi-Fi does not | Wireless radio or client driver | Reboot AP, update Wi-Fi driver |
| All devices lose access at once | Router or modem hang | Power-cycle modem then router |
| Slow drop after firmware update | Bad firmware image | Roll back to previous firmware |
Prevention
- Reboot the router on a monthly schedule using its built-in timer to clear session state.
- Keep a spare Ethernet cable and a printed copy of the ISP PPPoE credentials on site.
- Set DNS to a reliable resolver (for example 1.1.1.1 or 9.9.9.9) as a fallback.
- Log firmware versions after each update so you can identify a bad release quickly.
FAQ
How do I know if the problem is my router or my ISP?
Look at the modem's WAN or internet LED first. If it is off or red, the line is down and the issue is with the ISP. If the WAN light is solid but no device gets traffic, disconnect the router and plug a laptop directly into the modem. Working traffic there isolates the fault to the router.
Why does my Wi-Fi say "connected, no internet"?
The laptop associated with the access point but cannot reach the wider network. Common reasons are a failed DHCP lease, a broken PPPoE session on the router, or DNS servers that stopped responding. Run ipconfig, check for a valid gateway, then ping the gateway, then 1.1.1.1, then a hostname to find where it breaks.
Is factory-resetting the router safe?
Yes, but it erases Wi-Fi names, passwords, port forwards, and ISP login details. Before you press the reset pin, export the configuration if the router supports it, and confirm you have the PPPoE username, password, and any VLAN ID from your provider. Without those, the router will not reconnect after the reset.
Still offline after these checks? Contact our IT support team for hands-on diagnosis.