Modem Has No Internet, Online Light Off or Blinking

The modem is the box that talks to your provider. If it cannot get online, no router behind it can fix that. The modem's lights are the diagnosis: a healthy modem shows a solid power light and solid downstream, upstream, and online lights. Any light that never goes solid tells you where the connection stops.

The fix, in order

  1. Read the lights and note which one stops. Power should go solid within seconds. Downstream blinks while searching for a signal, then goes solid. Upstream blinks while handshaking, then goes solid. Online blinks while authenticating, then goes solid. A full boot takes one to five minutes.
  2. Wait out the boot. After plugging the modem in, wait up to five minutes before deciding it has failed. Rebooting every 30 seconds restarts the connection process each time and guarantees it never finishes.
  3. Power cycle properly. Unplug the modem from power for a full 60 seconds, then plug it back in and wait up to five minutes for the lights to settle.
  4. Tighten the line cable. For cable internet, finger-tighten the coax cable at the modem and at the wall. Remove any unnecessary splitters, each one weakens the signal. For DSL, check the phone cable and any filter. For fiber, check that the fiber cable is seated and not bent sharply or damaged.
  5. Check for an outage. Using mobile data, check your provider's status page or app. If the downstream light never goes solid and there is a known outage, wait it out.
  6. Try a different outlet and cable. A failing power adapter can make a modem behave strangely. If you have a compatible spare adapter, try it. If the modem is more than five years old and the lights never settle, it may be failing.
Never open a modem or try to repair a fiber cable yourself. A damaged fiber line and a faulty modem are provider-side problems, and tampering with them can make the repair slower and more expensive.

If it still happens

If the online light never goes solid after a proper power cycle, tight cables, and no outage, the modem usually cannot authenticate with your provider. Common causes are an unpaid or suspended account, a modem that was never activated or registered with the provider, or a line fault. Check your account status through your provider's app or website, then contact the provider through its official support channel and report which lights never go solid.

Common questions

How long should a modem take to come online? Most cable modems finish booting in one to five minutes. If any light is still blinking after five minutes, something is wrong with the signal, the line, or the account.

My modem's online light blinks but never goes solid. What does that mean? The signal is usually reaching the modem, but it cannot finish authenticating with your provider. Check your account status first, then check whether the modem needs to be activated or registered with the provider.

Should I factory reset my modem? Only as a last resort. A power cycle fixes most modem problems, and a factory reset wipes settings for no gain in most cases. If the modem was supplied by your provider, ask the provider before resetting it.

Related guides

Router Has No Internet · Router Red Light · Modem Power Light Blinking · Router PPPoE Authentication Failed

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