Official Websites Being Blocked For Unknown Reasons

Hi,

I've been getting these warnings from my browser when trying to access legit websites. So far I can't go to amazon, gumtree and a few others I cannot remember now.
It's weird because I've used these links before and I know they are the legit ones but my browser keeps telling me no.

I took a SS of me trying to access gumtree, but for some reason it's not letting me upload it. But I'll copy it to this thread below cos it won't fit in 1



What does this mean?

Also, I do not know if this is relevant but 1) I had someone from here help me remove a virus recently and 2) I got a upgrade from copper to fibre for my broadband meaning new router and such.

Cheers

 

Your connection is not private
Attackers might be trying to steal your information from www.gumtree.com (for example, passwords, messages, or credit cards).

NET::ERR_CERTIFICATE_TRANSPARENCY_REQUIRED
Automatically report details of possible security incidents to Google. Privacy policy
www.gumtree.com normally uses encryption to protect your information. When Chromium tried to connect to www.gumtree.com this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be www.gumtree.com, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Chromium stopped the connection before any data was exchanged.

You cannot visit www.gumtree.com right now because the website uses HSTS. Network errors and attacks are usually temporary, so this page will probably work later. Learn more.

 

This reads like Chromium is outdated, can you install the most recent version, or the latest Chrome/Firefox/Opera and test again?

 

That's about right. For some reason this didn't auto-update or notify me.... Anyway, updated and websites unblocked. Was doing my head in so thanks.

 

No worries, pleased it was an easy fix for you.