"No cypher overlap error" in web browser

[#1]

When using my plusnet broadband I am getting a "no cypher overlap" error in my browser when accessing some websites eg https://support.startpage.com. The exact error message depends on which browser (chrome/firefox/edge) I use. Error occurs both via wifi and ethernet

If on the same machine and browser I connect over a 4G mobile phone signal I don't get the error. I've tried rebooting the wifi modem/router, which is a BT SmartHub

Can anyone help?

Nick

[#2]

Hey @NickKnows,

I'm sorry to hear about this. Please could you try deleting your web browsers cache and cookies?

[#3]

Cleared the history on my firefox mobile app, plus cleared the cache and data using Android settings. No change in behaviour. This problem affects all browsers Firefox/Edge/Chrome across all my devices (2 PCs my Android phone and an Android tablet)

[#4]

Thanks for confirming this. I'm sorry to hear that's not done the trick. Tonight, please could you turn the router off overnight and then back on again in the morning to see if this resolves the issue? 

[#5]

Hi, the router was powered down for 9 hours last night, problem has not changed. What I have discovered is that the website causing the problem https://support.startpage.com only supports TLS1.2, it does not support TLS1.3. Checked this out using https://www.ssllabs.com. Could this be relevant?

[#6]

Hi @NickKnows, thanks for getting back to us. Although my knowledge on TLS is somewhat limited, I'm fairly sure that both TLS1.2 and TLS 1.3 are the current accepted when it comes to web hosting so wouldn't think this is behind the issue. Are you able to access the site fine on your mobile (separate device) using the routers connection? I'm hoping this helps further in narrowing down what's behind this for you.
I look forwards to hearing from you further.
 

[#7]

The behaviour on my android mobile is this

Using my android phone with wifi via the router

support.startpage.com is unreachable on both Chrome and Firefox mobile

startpage.com is OK with Chrome, but blocked in Firefox mobile

Using my android phone with wifi turned off (so only the 5G signal)

support.startpage.com is OK on both Chrome and Firefox mobile

startpage.com is OK with Chrome and  Firefox mobile

[#8]

Hi @NickKnows, thanks for getting back to me. I'm sorry to hear the issue looks to persist and seeing this on a separate device on the same connection certainly points towards an issue with the connection.
I've spoken with a few colleagues from here then in regards to what factors of the connection could be causing this issue for you and we've come up with a few further checks to do in hopefully narrowing down the cause of this further.

Firstly, if you have safeguard enabled on your account it could be something relating to this behind the error message you've seen. I'd advise then, rather than disabling the safeguard to instead change the DNS settings with one of your 2 devices which will bypass the safeguard.
This should both rule out safeguard and the default DNS settings as being the cause.

Steps on how to adjust your DNS settings on a device can be seen here:
https://developers.google.com/speed/public-dns/docs/using

Let us know how it goes and if issues persist as there's further steps we can try.

[#9]

I changed the IPv4 DNS settings on one of our Windows 10 PCs to use the Google DNS and this resolved the problem. So is the next step to restore the DNS to the automatic settings and try switching Safeguard off?

[#10]

Ah great news! Yeah, this then points towards either the DNS settings or safeguard as the cause. So yes if you can please, log into the member center and disable your safeguard to see if this then allows you onto the site with normal DNS settings. Let us know how it goes.

[#11]

I disabled safeguard overnight and can now access the page that was causing problems

[#12]

Thanks for getting back to us and confirming how it went. I'm glad we've worked out the root cause of the issue. In which case, I've raised a task with our products team to look into this page being blocked and they'll hopefully correct this for us. So you can turn safeguard back on I'd advise adding the site address to the allow list for now.

[#13]

Thanks for that. One other question I suggest you ask the products team is why attempting to access this page causes a "cypher error" message, instead of the usual page that appears when a page is blocked by safeguard? The latter explains that the page has been blocked and gives the user the option to put in their plusnet password to overide the block.

[#14 · Accepted solution]

Ah good, point. Had the block page displayed the correct message then this issue could have been resolved sooner. I'll add this to my query but I'm not too sure they're be able to confirm why. If they do I'll be sure to let you know.
If there's anything we can help you with moving forwards then please don't hesitate getting back in touch.