If your router says internet disconnected but the modem is online, check the WAN cable, confirm the WAN port, then restart modem first and router second.
If the router still has no WAN IP, test the modem directly if allowed, then check WAN mode, MAC registration, bridge mode and provider activation.
Start with the real failure point
When the modem or fiber box says online but the router says internet disconnected, the failure is usually in the handoff between the two boxes. The modem may have provider signal while the router fails to receive a WAN address, gateway or DNS. That can happen after a power outage, a new router setup, a weak Ethernet cable, a wrong WAN port, a stale DHCP lease or provider equipment that still remembers the previous device. It looks like the whole internet is down, but the clue is narrower: the modem and router are not agreeing on the outside connection.
The practical fix is to move along the path in order. Check the modem light, replace the WAN cable, read the router status page, restart modem first and router second, then test WAN settings. That order prevents a messy factory reset when the real issue is just a cable, lease or provider registration.
Quick diagnosis table
Try these fixes in order
Use this order so you prove the scope of the problem before you erase settings or blame the wrong part of the network.
- 01
Check the WAN cable and port
The modem or ONT should feed the router WAN or Internet port. Use a known-good Ethernet cable even if the port light turns on, because a weak cable can still fail under traffic.
- 02
Restart in the right order
Unplug both boxes. Power the modem first and wait until the online light is stable. Then power the router so it asks for an address after the modem is ready.
- 03
Read the WAN status page
Look for WAN IP, gateway and DNS. Blank, disconnected or 0.0.0.0 means the router is not receiving a usable outside address.
- 04
Release and renew the lease
If your router has release or renew controls, try them once. This can clear a stale DHCP lease without wiping Wi-Fi names and passwords.
- 05
Test directly at the modem
If your provider supports it, connect a laptop by Ethernet to the modem for a short test. If it works there, the router side is the suspect.
- 06
Check WAN mode and MAC registration
Some providers require PPPoE, VLAN, static IP settings or a registered MAC address. Compare with the old router or ask the provider to refresh provisioning.
- 07
Call support with the right wording
Say the modem is online but the router has no WAN connection. That points support toward the handoff instead of a basic Wi-Fi script.
Detailed checks
Connected is only the first step
The router can still provide a local network while its internet side is broken. The useful proof is a valid WAN IP, gateway and DNS from the modem or provider.
- This distinction keeps the fix focused. If only one service fails, fix that service path. If everything fails, move to DNS, router rules and the broader connection.
Cache and account issues look like internet issues
A stale DHCP lease, wrong WAN mode or bad cable can make healthy provider service look broken from inside the house.
- A modem-first restart, WAN lease renew or provider provisioning refresh can fix that without erasing the router.
Router settings matter after comparison tests
If a direct modem test works but the router WAN status stays disconnected, the modem is probably capable and the router handoff needs attention.
- Change one setting at a time. Slow, clean testing beats an hour of guesses.
Mistakes to avoid
Do not plug the modem into a router LAN port unless your setup specifically uses access point mode.
Do not assume modem online means the router has a valid WAN address.
Do not call it a Wi-Fi problem if wired devices also have no internet. Start at the WAN side.
FAQ
Why does the router say disconnected when the modem is online?
Because modem online and router online are different checkpoints. The modem can have provider signal while the router still has no WAN address or route.
That is why the fix starts with scope. If the router has no WAN IP, stay on the modem-to-router handoff before changing Wi-Fi settings.
Should I reset everything first?
No. A full reset creates extra work and often misses the real cause. Restarting, updating, checking time and clearing local data are cleaner first moves.
Use factory reset only after the smaller checks fail and you know your account passwords. It is a last step, not a shortcut.
Can DNS cause this problem?
Yes. DNS tells the device where to find app and service servers. A bad or filtered resolver can break one service while other internet activity still appears normal.
Try DNS as a controlled test. Keep the previous setting so you can reverse it if nothing improves.
Why does it work on another device?
Different devices use different apps, software versions, cached data and account sessions. A phone working does not prove the TV, router or streaming device is healthy.
It does narrow the problem. If the service works elsewhere on the same Wi-Fi, focus first on the failing device.
Why does it work on a hotspot?
A hotspot changes the network path. If the device works there, your home router, DNS, provider route or filters deserve attention.
Do not leave it on hotspot as the permanent answer. Use that result to repair the normal home connection.
Can router filters block only one app?
Yes. Parental controls, security tools and ad blocking DNS can block certain service domains while leaving other apps alone.
Pause filtering for the affected device only. If it works, build a targeted exception instead of turning protection off everywhere.
When should I contact support?
Contact support when the issue remains after restart, updates, account checks, DNS testing and a comparison test.
Bring exact details: model, software version, error wording and what still works. That saves time with support scripts.
Is this usually a hardware failure?
Usually not. Software, account, DNS, router settings and service reachability are more common.
Hardware becomes more likely when the device fails on every network, cannot update, overheats or keeps dropping the connection.
Outside references
- Router support
Official reference for model-specific support and troubleshooting context.
- ConnectionFixer related guide
Explains how ConnectionFixer verifies and orders troubleshooting steps.