BT Whole Home hubs have stopped working

[SueH]

Hi all
I have a NowTV router and use two BT Whole Home discs (one connected directly to the router) to get decent wifi on throughout my house; however, a few weeks ago they stopped working!  I did all the troubleshooting things without success, so BT sent me two replacement discs, but I still have the same problem.  The disc attempts to connect but ends up with a failure-to-connect red light.  The router itself is working fine.
BT is asking if the issue could be with the NowTV router... anyone know if it's possible that something changed with the router around mid June?  Or any other bright ideas?

I don't have anything else attached to my hub, just one PC.
I don't have any other mesh system in my house.  
I have tried switching the discs.
I have tried switching the cables on the two ethernet ports on the modem.
I have tried restarting the router.
I have tried resetting the router.
I have checked that the router is on a dynamic IP address.

[RoyB]

@SueH 

Can I take it you are long past the BT recommended troubleshooting steps?

I've recently changed my hub (router) and can no longer gain internet access via Whole Home Wi-Fi.

Please reboot your hub (router). If this doesn’t work, then try factory resetting your hub (router) by following the instructions in How can I reset my Whole Home Wi-Fi to the default settings? >

As this is all crucially dependent on the Ethernet cable linking the router to the first Hub, I would suggest using that cable to connect to the PC, if it is long enough, or easy to get the PC to a place where you can plug that cable in.

And see if that works, which would eliminate any problems with the cable or the router port.

Maybe you have done this already? But if not, try it and report back here.

[SueH]

Hi Roy and thanks for your ideas.
Yes, I've followed all the BT troubleshooting things and I've reset the router and the discs (several times!).  It's not a new hub either.  And yes, the ethernet cable (a new one, supplied by BT) goes straight from the router to the first hub (and to my main PC). 
BT's only remaining suggestion is that I take the discs to someone else's house and try them there... if they work somewhere else then the problem is to do with my router (or something) and I should contact NOW because something has changed in terms of how my router is interacting with the discs.
But I need to figure out who to ask that favour of!
It's all rather mysterious, not to mention infuriating!     

[RoyB]

@SueH 

You describe above that one Ethernet cable goes to two devices.

Either you didn’t mean that, or it works and it’s something I’ve never met, or it’s the root of your problem 😛

I take it you have tried using the other port on the router for the disc? And swapping which disc is the router one, and which remote?

Have you tried asking Now for a replacement router? It’s just about possible that the one you have has gone faulty.

[SueH]

You're right... I haven't invited a way to get the two ends of a cable into three places😁.  But yes, the main disc is connected directly to the modem, and the modem is connected directly the main PC.  

I've tried switching the two ethernet cables where they connect to the modem (it only has two ethernet ports).  And I've tried connecting the other disc - I can't switch them as such because I've never got the first disc connected, so have never got as far as installing the second disc  (or rather, reinstalling, as they both used to work).  
Thanks for the idea of calling Now, I'll try asking them for a replacement router.  Though I think they may not be interested in that the router's working (it's providing me with broadband), it's just no longer communicating with the BT discs.... But it's got to be worth a try!
Thanks for your help Roy.

[SueH]

NowTV chap was helpful, but basically my router is working fine and he said to go back to BT.  They understandably won't send a new router because it's working, and apparently its their most uptodate model - but also out of warranty, so it would cost me £39 to replace it, which he advised against.