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Full Fibre - PON flashing light

Pigaroo1076 — Mon, 10 Nov 2025 09:14:05 GMT

Hi, had full fibre fitted on Friday and has worked fine all over the weekend. This morning the PON light was red, so I turned off the ONT and now I have a continuous flashing green light. Tried to call BT but keep getting directed to 61998 bot which seems to just go around in circles. From reading other posts I think it is an account issue which may be fixed over the phone - how can I talk directly to someone?

Re: Full Fibre - PON flashing light

iniltous — Mon, 10 Nov 2025 09:45:19 GMT

The red light was a LOS (loss of signal) indication and a green flashing PON light is an indication that there is a signal but your ONT hasn’t been recognised at the ‘headend’ equipment, where previously it had (because it worked for a time ) .

This is effectively two different problems, in basic terms you had no ‘light’ coming into your ONT , and that’s been replaced by having ‘light’ but from the wrong place …a scenario that could provide a set of circumstances that would account for that , is a cable fault between the headend and splitter node (so for arguments sake someone cuts an optical cable containing many ‘connections’ ) , when reconnecting /repairing the damaged cable someone makes an error , so instead connecting fibre A to A , B to B , C to C etc, they connect A to B , B to C , and C to A , obviously I’m not saying that is the issue here (and my example is over simplified to hopefully aid understanding) but something like that could explain someone experiencing 2 errors in succession…there are other possibilities, like your ONT has developed a fault and has stopped communicating with the headend , but I’m not trying to identify your specific problem, just indicating the type of thing that can happen in the network.

Its not likely to be an account issue with BT , that is more likely to show up as you having a solid green PON light on the ONT , and an error light on your router , but it’s unimportant anyway , even if the error is on the Openreach network you need to contact BT who in turn need to advise Openreach .

There is a pretty reasonable chance that if it’s Openreach’s problem affecting many customers , they already know about it ,(perhaps ask near neighbours on Openreach FTTP if they are having issues ) but you still should report it to BT , that way should the delay in repair take some time, at least your fault is recorded with BT so any compensation can be calculated

Re: Full Fibre - PON flashing light

Pigaroo1076 — Mon, 10 Nov 2025 09:53:57 GMT

Thanks for the response - how do I report a fault? I’ve used the text bot and it says someone will be in touch - when I check on my account, there is no fault registered

Re: Full Fibre - PON flashing light

iniltous — Mon, 10 Nov 2025 10:19:31 GMT

The only recent experience I’ve had was I tested my line via ‘My BT’ , an external fault was picked up by the tester , in my case FTTC was working but at around 40Mb instead of the usual 80Mb , the system automatically reported it on my behalf , basically it said something along the lines ‘ there is a fault , we have advised our supplier’ and the next day a Kelly’s/Quinns contractor knocked on my door , and repaired the issue within around 30 mins .

As you are FTTP , I’ve no idea if the process is similar, or if online testing with automated fault reporting is ineffective and you would need to call and navigate through the ‘bots’ to speak to a human …in a different industry the last time I had to get past non human interactions was by ignoring the prompts (press 1 for whatever ) and saying ‘connect me to a human’ , it eventually did work but I appreciate that these AI systems and Bots are designed to frustrate you to the point of giving up , it’s not just BT that are guilty of this .

TBH if the text reply says someone will contact you , not having a fault record yet is understandable, after all if they called a customer who has reported a fault, and asked them to check the power was on and they sheepishly came back and said someone had unplugged the ONT , that’s not a fault that needs recording, presumably the recording takes place once the location of the fault is established

Re: Full Fibre - PON flashing light

chrisjp — Mon, 10 Nov 2025 12:06:16 GMT

"Thanks for the response - how do I report a fault?"

I recently needed to report a fault and went online to www.bt.com/exp/engineer-booking, logged into my account and got a BT technician to my house within a few days.

Re: Full Fibre - PON flashing light

Pigaroo1076 — Mon, 10 Nov 2025 12:26:52 GMT

Thanks - the fault has now been registered and an engineer is coming out this afternoon - fingers crossed it gets sorted I’ll let you know how we get on 👍