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.

[AkiTaiyo]

Yep, was purely coincidence that I'd had a day without error.. about an hour after writing that post, back to errors again.

[bytespider]

I took get days where I think all is good and others where every other request gets EOF

[AkiTaiyo]

On the plus side, it looks like I can get out of my contract without any early leaving charges..

[AkiTaiyo]

Well, I've wasted more than enough time on support calls with people that just follow the same script over and over again, "reset the router", "the problem is with the app", "is the 5g light on"..

Time to change provider.

[AkiTaiyo]

Must also note that just changing DNS doesn't mean the problem goes away, theres nothing to say the resolver wont give you the failing location at some point in the future..

[AkiTaiyo]

Changed my DNS from my own resolver to use Cloudflare with Quad9 as backup.. No more problems with any of the sites I've been having regular issues with..
From my limited testing, these were all served from Akamai, but if wgen has also seen the problem from other CDNs, then a DNS change might not be a complete solution.
If anyone has a non-Akamai URL that fails regularly (I was using visualsudio.microsoft.com because it failed so frequently!), I can also test the URL through Three and other connections to see if is a similar issue with different data-centers.

[bytespider]

DNS did nothing for me. I've had some success with disabling IPv6 features including DHCP/RA but that's anecdotal as I've not browsed much to be able to notice of it's helped  

[AkiTaiyo]

Yeah, the DNS change has only affected some sites.  I keep coming across more failing sites the more I browse. 
I also have all IPv6 features turned off on the router.

[bytespider]

Can confirm, disabling all IPV6 features does not help.

[EDIflyer]

Yep, I tried that a few months ago to no avail.  Having more issues with my smart TV recently @JonathanB can we have another update please? Surely given the number of customers being affected this is being looked at in depth and there should be weekly progress reports to senior management?