Intermittent connection issues loading/changing site- secure connection failed/site can't be reached

[EDIflyer]

Is anyone else occasionally getting a 'connection down' error from Chrome (or 'Secure Connection Failed' from Firefox) when changing page - if I hit refresh it works fine. At first I wondered if it was the site I was using but have noticed it on multiple different major websites over the past couple of months and not noticed it from other locations where I don't use Three Broadband so does seem to be related to the router/connection (this is via wired Ethernet too, so not a WiFi problem).  I've tried changing DNS server in case that helps but no difference.

It mainly seems to happen when trying to first load a site or (annoyingly) at checkout when a different site is being loaded as part of the checkout process.  It certainly doesn't happen everytime but does happen with reasonable frequency.  I've also noticed I often get it when trying to pull/push from/to Github too and have to do so a number of times for it to work (browsing the Github website works fine).

I'm using a NR5103E with Firmware Version V1.00(ACBJ.0)b14 - I tried rebooting it but to no effect.

[Nameless]

Just a quick check-in

I moved the router and tested both Wi-Fi and Ethernet and the problem is still there although it took longer to see it as I have been connected to Band B1 lately despite all bands being enabled

Usually, if I am connected to Band B3, I encounter the PR_END_OF_FILE_ERROR at some point whilst going through the list of problematic sites once. Today I went through the list twice in immediate succession then started a round of speed tests for ~15 minutes due to the router's new position being closer to the nearest mast by ~3m-5m. After that, I encountered the problem when going through the list for a third time

The router's last uptime was ~51 days if I read it correctly before turning it off

How are things for all of you?

[AlSeek]

More or less the same as usual for me. As mentioned long ago in this thread, I am running my router as 4G only and get the connection issue infrequently. In 5G mode I get the error frequently. So that may be band related or maybe not, I don't know.
I have tried going on 5G and disabling band B3 which made no difference to me since I still got the error quickly.
Indeed connected by 4G right now I'm apparently on bands B3,B32,B1 and the issue is currently infrequent.

[Nameless]

The error is definitely somewhere in Three's infrastructure although I have not tested any of the 4G bands alone as extensively as I have tested them in combination with the N78 5G band

Have you tried the 4G bands individually? It would probably have the biggest impact on your speeds compared to using a VPN or Cloudflare's WARP although these are currently the only known methods of avoiding the highly variable PR_END_OF_FILE_ERROR completely

I will try testing the 4G bands individually when I get time

[EDIflyer]

Did anyone else have major issues last night? I found from about midnight until 9am my internet was completely down unless I used a VPN.  Phone showing an exclamation mark over wifi and 'offline' in Chrome, PC wouldn't connect to any site. However once VPN activated then all working OK - it was like a more extreme version of this issue!

[Nameless]

Thank you for mentioning this

My internet has become somewhat more unstable in the last few days however, apart from when I have been doing tests, my main indicator is that the Amazon Fire TV has been stuttering a lot over the last few days but this has been far more noticeable on higher resolution streams (FHD+) and for content that uses a high frame rate

[JonathanB]

Hi @EDIflyer,

I've had a check and we don't have any major widespread incidents reported, so it might have been more local of an issue. Glad to hear it was relatively short term and seems to have been fixed this morning.

Were the browser errors matching the usual "end of file" or "connection closed"?

Thanks,
Jonathan

[EDIflyer]

Thanks for checking @JonathanB - I think you've got my details on file so would be interested in you saw anything reported locally (my mobile is on iD Mobile that use 3 and had similar issues).  It was actually worse than the usual EOF/connection closed - I actually couldn't browse any sites at all but weirdly could still connect to my VPN and then everything worked fine. I suppose I was just wondering if it was a bigger version of this issue but may of course have been totally unrelated!

[Nameless]

A check-in for the new year with no changes

Hopefully this will be the year when these internet issues are put to rest for good

Although I am still busy at this time, I will try my best to continue making weekly updates

If any of you have encountered any changes, please let us know

[JonathanB]

Hi Everyone,

Sorry for the delay since the last update. We're still investigating the issue and have gathered some live trace data which is being analysed for more insight. We're also arranging some more internal testing. we haven't been able to reproduce the issue on our side in the past but we're hoping that the info gathered more recently will help us do so. Hopefully we'll have more to share about this soon.

Thanks,
Jonathan

[Nameless]

Hello and thank you for your update

Just to make sure, if you and the other Three staff members have a different way of accessing the network infrastructure compared with your customers then that could be a reason why you do not seem to notice these issues

For your tests, please make sure that you and the team(s) at Three are using a setup that is identical to a customer's setup including, but not limited to:

• Router used, its firmware and its settings
• Same default APN settings
• PC/Mac/Linux computer/laptop with no extra software operating between the web browser and the operating system in regards to using the internet
• Android/Apple mobile device with no extra software operating between the web browser and the operating system in regards to using the internet

Although I usually test on a PC running various forms of Linux and its associated extras, I have seen errors on the following devices:

• Laptop running Windows 10 as new (Same error messages)
• Apple iPhone 11 Pro Max (Manifests as website connection errors)
• Nintendo Switch (Manifests as internet connection errors)
• Amazon Fire TV (Manifests as internet connection errors or website connection errors)

I always test the latter two devices with either a PC, laptop or the iPhone mentioned as they are unable to report the specific issue but are always momentarily affected whenever I hit the PR_END_OF_FILE_ERROR when testing extensively and have used all of these devices on two Three provided routers:

• ZTE MC801A (I think that is the correct model)
  
• Zyxel NR5103EV2

I would have tested on a Zyxel NR5103E but the SIM slot was broken...

Although it has been a very busy time, I will still continue to do my tests although I may be a bit delayed with my own updates at this time