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.

[BrummyGit]

I think it's my fault that the issues around some sites such as malkoffdevices.com are being discussed. I was helped by a user on another forum and turning off the Adult Content Filter resolved all of my permanent connection issues (but not the intermittent ones that are the main subject of this thread), so sorry I think this was a red herring.

[BrummyGit]

Can anyone who suffers from the intermittent secure connection issues try the following link https://malkoffdevices.com/products/malkoff-hound-dog-super-flashlight - it is just a torch seller in the usa however I reliably get an SSL error when I try to load the page from my Three Broadband, but if I use my BT wired service it loads fine. I'm hoping this is a repeatable example of the problems we are seeing.

[JonathanB]

Thanks @BrummyGit, I'm sorry I didn't get a chance to reply but we passed this example over last Friday too.

[robjames_1]

That website seemed to work just now for me but have been having similar issues for a couple of months. 
Notably online payments and online banking apps are hit or miss. Disney plus, and my5 don’t work but strangely Netflix and prime do. 

[EDIflyer]

Yep I find online payments particularly buggy - just at the time you don't want a transaction to fail!

[BrummyGit]

With the help of a user on another forum, I have worked out that my consistent inability to reach certain websites is due to the Adult Content filter (even though they aren't adult sites). Turning it off has resolved that issue.

I have a slim hope that it also solves the intermittent secure sites problem, but I honestly doubt that. Time will tell

[baztm]

I get the error inconsistently on seemingly any website. For now your link seems to be working, but I had facebook throw up the connection dropped earlier.

[Tatablack]

Hi! If you check my previous post on page 2 of this thread, you'll see the method I used to test connections (from the command line).

Could you also verify that switching your router to 4G "solves" the issue?

By the way, I tried the website you mentioned, and indeed it fails consistently, even though with a different error than others:

curl: (35) LibreSSL/3.3.6: error:1404B419:SSL routines:ST_CONNECT:tlsv1 alert access denied

If I try it from my mobile, after switching to the mobile network, I can confirm it works without problems.

[BrummyGit]

I tried switching to 4G recently but whilst it reduced the number of instances, I did still have problems. My hunch is that it is loading related (not sure if that's my local connection or the 5G network) - I have been using the internet quite a lot today, however there is very little load, and I haven't had a single occurrence. It could be that slower 4G speeds mask the issue.

I only run windows and therefore your test won't work for me.

[BrummyGit]

I've been trying to further diagnose my issue and have the following information that might be helpful:

• Most of my errors are SSL errors or QUIC protocol issues on Chrome
• I see more problems in an evening than during the day - network load related?
• Swapping the IP Passthrough mode does NOT solve the problems
• Disabling IPv6 everywhere in the router config does not solve the problems
• Using external DNS directly from my clients does not solve the problems

This is frustrating as I am in my 30 day returns window and I was hoping to find a faster alternative to my BT FTTC service however it currently isn't reliable enough as I work from home. Is there any option for me other than cutting my losses?