Strange issue - router sync'd but no internet

[#1]

Woke up this morning to find everything offline.  The router (TP-Link Archer VR2800) has been running perfectly for ages and still shows as syncing with Plusnet.  However the Internet section shows as disconnected on the home screen:

Internet: Disconnected

"Please configure your DNS manually."

Connection type: PPPoE

IP Address: <shows my WAN IP>

DNS Server: 212.159.6.10  212.159.6.9 (these should be Plusnet's DNS server IPs I think?)

Gateway: 172.xx.xx.xx

However, looking under the Advanced > Network > Internet Connections tab it's showing as 'Connected'...

WAN Interface name: pppoe_ptm_101_0_d

VPI/VCN or VID: 101

Status: Connected

I was using Cloudflare's DNS (1.1.1.1 and 1.0.0.1) which were working fine until this morning.  Have swapped back to my BT Hub6 to test (shows 'connected' but no internet) and the same with the original white Plusnet hub which I managed to locate and plug in for testing.

Spent ages on the phone with support this morning, have removed and recreated the connection profile in the TP-Link etc - all to no avail.  The TP-Link actually shows all LEDs as white (which is as it should be in usual operation) although I'm bemused that it thinks everything's fine when in fact it isn't.

I've tested with 3 different routers, 2 PCs, a laptop (wireless and hardwired) and my phone - nothing works.

The sync speed shows up OK as well:

Current Upstream: 17566 (max 17643)

Current Downstream: 48997 (max 63933)

SNR Margin dB is 6.1 and6.9 up/down

Line attenuation dB is 25 and 13.5 up/down

I don't think it's a line fault (as the sync is bang on what I'd expect) but the support guy was out of options.  I'm now in the hands of the Fault team which could take up to 72 hours just for a response.  Not ideal when I'm working from home and up against it enough already.

Has anyone else got any ideas, thoughts or recommendations to try from my end to try and fix this in the interim or is it likely to be on Plusnet's side to solve?

Cheers.

Edit: worth mentioning that the line was apparently 'banded' and that was removed/reset last week apparently - not sure whether that would have anything to do with it?  We also removed my static IP to see if that was the issue but that didn't fix anything.

[#2]

Thanks for your time on the phone @Funk I'm sorry for the problems with your connection. This is a really odd issue, as discussed I've raised a dial test to rule out or confirm an issue with your account itself. I've also booked an engineer for Tuesday Morning between 8am and 1pm as a backup plan.

I also plan to contact BT's quality assurance team tomorrow to check the S-VLAN at the exchange as there's potential that this may be a severe throughput problem.

I'll call you back tomorrow as soon as I know more with hopefully some good news.

[#3]

Morning Gandalf,

Thanks for your help yesterday - good news; whatever happened overnight following our conversation has restored the connection - it's back up and running.  Looking at the sync speed it's apparently still banded to 44993kbps, however.

I know you mentioned that the original request was back on the 1st July but could you re-initiate it now we've got connection back again? The router thinks the max rate should be itro 64973kbps so if I can get even a 10-15,000kbps bump that'd be great.  Upstream looks fine.

I think we can cancel the engineer too now the connection's back up. 👍

[#4]

Cheers for your time on the phone @Funk 

Really glad to see you're back up and running now although the cause seems to be a bit of a mystery.

As discussed I've submitted a DLM reset and I'll follow things up with you on Thursday.

[#5]

Bumping an older thread of mine; my line seems to have been banded back on to a lower speed again - it's showing download at 43993 with a max rate of 54828.

Is there any chance of a remote DLM reset again please?

[#6]

I've arranged for a DLM reset now which should go through within 3 working days.

[#7]

Thanks Gandalf, it's already jumped to 58619 (max 57688) with a not-unexpected increase in errors, be interesting to see where it settles down to again...

What I really want is FTTP but no idea when that might be coming to my area unfortunately!

[#8]

Been limited again to 43998... Please could you request a DLM reset again for me Gandalf?

After months of being stable I've had several random disconnects in the last couple of weeks; not been great...

[#9]

...and now on exactly 40,000.  Something's not right...!

It should be up around 56,000.

[#10]

@Gandalf 

My line's re-banded back to 43998 again (ARGH!), please could you trigger a DLM reset for me?

[#11]

@Funk  You might have already had a look here to see what you should be getting. But given you've already had a DLM reset and ended back down, and assuming it is well out of kilter with what shows in the link i.e. impacted line? etc. I'd be asking questions about whether the line / equipment needs testing/ checking.

While many years ago DLM was a pain (was there myself for a couple of years with it), over the years I've found it has improved, such that if the line is naff at a sync rate, it will set that line slower for a reason. Conversely, it will automatically retrain it higher if it gets better. No point having a line syncing higher than what is reliably achievable. All that happens is the errors increase, such that data is having to be resent and that will slow things down. And then in kicks DLM and you end up back where you were. As you have. 😞 Vicious circle.

I would say my time at my last ISP was pretty enlightening when it comes to DLM being active because there I had direct  access, via the supplied portal, to see the retrains - I had 3 in one day with about 30 taking place over the next couple of weeks. Eventually the line did fall over. Once repaired it was full speed once again but even then months later I saw that every so often DLM would kick in, moving the line speed up or down a touch.

[#12]

@idonno

Cheers for the comments, I already know the line should support around 65000kbps so it's at 2/3 what it should be.  Openreach checked the line recently and it had a clean bill of health.  There were roughly 1100 pkt errors (downstream) over the last couple of days so not excessive.

Upstream sync is bang on as expected.