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What to Do When Your Broadband Goes Down

A step-by-step troubleshooting guide before you call your ISP.

Don’t Panic

Your internet has stopped working. Before you spend 45 minutes on hold with your ISP, run through these checks. In most cases, you can fix the problem yourself in under five minutes.

Step 1: Check the ONT

The ONT (Optical Network Terminal) is the small white box on your wall where the fibre cable enters your home. It has LED lights on the front.

  • All lights green/solid: The fibre connection to CityFibre’s network is fine. The problem is likely your router or your devices.
  • Red light or flashing amber: There is a problem with the fibre signal. This could be a network fault or a damaged cable. Skip to Step 4.
  • No lights at all: Check that the ONT is plugged in and the power socket is switched on. This sounds obvious, but it is the most common cause of outages, especially after someone has been hoovering near the socket.

Step 2: Restart the Router

If the ONT lights look normal, restart your router.

  1. Unplug the router from the mains.
  2. Wait 30 seconds. This clears the router’s memory and forces it to re-negotiate the connection.
  3. Plug it back in and wait 2-3 minutes for it to fully boot.

Most intermittent broadband problems are caused by the router’s software getting into a bad state. A restart fixes this more often than not.

Step 3: Test with a Cable

If the internet is still down after restarting, plug a laptop or PC directly into the router using an Ethernet cable. Open a browser and try loading a website.

  • Works on the cable but not Wi-Fi: Your internet is fine. The problem is your Wi-Fi. Try moving closer to the router, switching from 2.4GHz to 5GHz (or vice versa), or restarting your device’s Wi-Fi.
  • Doesn’t work on the cable either: The issue is between your router and the wider internet. Move to Step 4.

Step 4: Check for an Outage

Before calling your ISP, check whether there is a known outage in your area. Most ISPs have a service status page on their website, or you can check their social media accounts. CityFibre also publishes network status updates. If there is a known fault, there is nothing to do but wait. These are usually resolved within a few hours.

Step 5: Contact Your ISP

If you have ruled out power, restarted the router, tested with a cable, and confirmed there is no known outage, it is time to call your ISP. When you do, having this information ready will speed things up:

  • Your account number
  • The colour and state of the ONT lights
  • Whether you have already restarted the router
  • Whether the problem is on Wi-Fi only or also on a wired connection

This saves you from being asked to “turn it off and on again” by the support agent, because you can tell them you have already done it.

Preventing Future Issues

  • Keep firmware updated: Most modern routers update automatically, but check your router’s admin page periodically.
  • Avoid overloading power sockets: Plugging your router and ONT into an overloaded extension lead can cause intermittent power drops.
  • Consider a UPS: If you work from home and cannot afford any downtime, a small Uninterruptible Power Supply (£30-£50) will keep your router and ONT running through brief power cuts.