troubleshooting

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Your phone still has full wifi bars. The laptop says it is connected. And yet every few minutes the whole house goes dark at once, the smart speaker stops mid-sentence, the work call freezes, and then it all comes back as if nothing happened. Wait twenty minutes. It does it again.
That pattern matters. When one device loses wifi, you have a wifi problem, and that is a different post. When everything drops together, the connection itself is dropping, and the fix lives further down the wire than your router's wifi.
This is the bit that separates this problem from every other broadband complaint. A dropping line is very often not your fault at all. So as well as telling you which of three causes you are looking at, this guide tells you the exact wording to take to your provider, and the money Ofcom says you are owed when it is their mess to clean up.
Before anything else, take wifi out of the picture. Plug a laptop straight into the back of the router with an ethernet cable and use it for a few minutes.
If the wired connection stays up while your wifi keeps dropping, the line is fine and you are in the wrong guide. Your problem is wifi, and the wifi-keeps-disconnecting walkthrough is where the answer is. If the wired laptop drops too, the connection itself is going down, and you are in exactly the right place.
While you are here, check whether your area is actually down. There is no point diagnosing your own kit for a fortnight if an engineer reversed a digger into a cabinet three streets over.
A line that drops for everything has three usual culprits. They look identical from the sofa. They are not the same thing, and they do not get fixed the same way.

A re-sync is a brief disconnection while your modem renegotiates its link with the cabinet or exchange. Plusnet, which runs on the Openreach network, describes it plainly: a change forces "a quick disconnection between your BT Openreach Modem and Cabinet" (Plusnet, FTTC DLM explained).
A few re-syncs a month is the line doing its housekeeping. Dozens a day is the line panicking. The usual trigger on copper or FTTC is electrical interference, a noisy appliance bleeding onto the pair, which the industry calls REIN. Full fibre does not get this, because light down a glass strand does not care what your dishwasher is doing.
And here is the bit that punishes you for trying. Openreach watches each FTTC line and, if it keeps re-syncing, decides the line is unstable and holds it at a slower, more cautious speed to keep it up. Plusnet calls this banding, where "the minimum is usually half the maximum" (same page). So the worst thing you can do with a flaky line is sit there rebooting it forty times. You teach the network the line is rubbish, and it bands you down. The fault gets fixed eventually. The slow speed can outlive it.
Sometimes it is just the box. The router freezes or reboots itself, the lights cycle through their start-up dance, and for a minute everything is down because the thing routing your traffic has gone away to think about its life.
The tell is the lights. A router crash usually shows the whole unit restarting, lights going off and coming back in sequence, rather than one specific broadband light dropping out on its own. The exact colours and labels differ by model, so check your manual rather than trusting a stranger on a forum about a hub you do not own.
The fix order is boring and that is fine. Power-cycle it once, properly, off at the wall for thirty seconds. Then check for a firmware update, because an out-of-date router is a router running last year's bugs. If it still crashes after that, the box is failing and your provider should replace it. Do not factory reset as a reflex. A factory reset wipes your wifi name, your wifi password and every setting back to default, and on an ISP-supplied router it can mean re-provisioning the thing from scratch. It is a last resort, not a Tuesday.
This is the one where it is genuinely not you. The drops correlate with something in the real world. They get worse in the rain. They happen at the same time every day. They started after someone dug up the pavement. The broadband light, not the wifi, goes out when it drops.

Openreach is blunt about who diagnoses this: "Intermittent problems can be caused by line faults, network issues, or even equipment in your home. Report this to your provider so they can test the line" (Openreach). You cannot ring Openreach yourself. "Only your provider has access to your service details and can raise a repair with us." So the line fault and the complaint route are the same conversation.
Whichever cause you have landed on, do one thing first. Log the drops. Date, rough time, how long each one lasted. A provider's first move is to claim they can see nothing wrong, and a fortnight of timestamps is how you stop that conversation dead.
Then use the right words for the cause. For a suspected line fault: "My connection is dropping intermittently and a wired device drops with it, so this is not wifi. I want the line tested and an Openreach engineer booked if the test cannot clear it." For a router that keeps crashing: "The router is rebooting itself repeatedly. I have power-cycled it and updated the firmware. I want a replacement unit." For relentless re-syncs: "My line is re-syncing dozens of times a day. Please check it before it gets banded down to a lower speed."
And now the bit no other guide on this page bothers with, because it costs the provider money. If your broadband stops working completely and is not fully fixed two full working days after you report it, the big providers pay you automatically. The current Ofcom rates, in force from 1 April 2026, are £10.34 for each day the total loss continues, £32.31 if an engineer misses a booked appointment or cancels with less than 24 hours' notice, and £6.46 a day if a new service starts late (Ofcom, 8 April 2026). It lands as a bill credit within 30 days, and you do not have to ask, "your provider will pay compensation automatically" (Ofcom scheme rules).
Two catches worth knowing. The scheme covers a total loss of service, so a line that drops and recovers all day, maddening as it is, often does not trigger the daily payment, though a missed appointment still pays out. And it is voluntary. Many of the largest providers are signed up, including BT, Sky, Virgin Media, TalkTalk, EE, Vodafone, Plusnet, Hyperoptic and Zen, but smaller altnets frequently are not, so check yours.
If they drag it out, you have a hard backstop. Once a complaint has gone unresolved for six weeks, cut from eight in April 2026, or you get a deadlock letter sooner, you can take it free to an independent ADR scheme whose decision binds the provider (Ofcom). How the compensation actually works and the ADR route when complaints stall are worth a read before you ring.
There is a point where the diagnosis stops mattering. If the line fault keeps coming back, if the engineer keeps closing the ticket and the drops keep returning, if the box has been replaced twice and still falls over, the verdict is the provider, not your kit. At that stage compensation is a consolation prize and a clean switch to another network is the actual fix. The wire under the pavement does not care which logo is on the router, but it does sometimes care whose engineers are looking after it.
Run a wired speed test before and after any change, peak and off-peak. It is your evidence, your before-and-after, and the one number that turns "it feels slow" into something a provider has to answer for.