Cannot access website due to invalid certificate

Question

Cannot access website due to invalid certificate

I cannot access The Guardian UK website from my MacBook (Sierra OSX) using Chrome, Safari or Neon browsers. The Safari pop up simply tells me the Guardian certificate "has an invalid user".

The Neon browser pop up is more informative (see below) but scary!

I am using WiFi and tried at both home and work WiFi connections - I get the same message.

From my work iMac I can access the website no problem at all.

So ... is there some malware on my MacBook I need to remove? A certificate in Keychain?

Or another solution?

This is only happening at the guardian.co.uk website though.

Many thanks.

MacBook Pro with Retina display, macOS Sierra (10.12), lives with iMacs, eMate & Newton.

Posted on Mar 2, 2017 9:18 PM

Reply

Answer 1

Eric Root

Level 10

685,221 points

Mar 3, 2017 5:36 PM in response to Michael Vallance

Try going to Applications/Utilities/Keychain Access and delete the certificate for the website. This should cause a new one to be downloaded. Quit and reopen Safari to test.

See if this helps.

Global Sign Invalid Certificate

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Answer 2

dominic23

Level 10

84,018 points

Mar 3, 2017 5:36 PM in response to Michael Vallance

Scam pop-up

1. Click  in the menu bar and choose “Force Quit”.

In the window that opens up, select “Safari” and click “Force Quit.

2. Relaunch Safari holding the shift key down.

Adware

3. Use Malwarebytes Anti-Malware for Mac to remove adware.

https://www.malwarebytes.org/antimalware/mac/

Download, install , open, and run it by clicking “Scan” button to remove adware.

Once done, quit Malwarebytes Anti-Malware for Mac.

4. Disable Extensions and test.

Safari > Preferences > Extensions

Select and disable all extensions and test.

Enable Extensions one by one and test.

To uninstall any extension, select it and click the “Uninstall” button.

5. Safari > Preferences > Search > Search engine:

Select your preferred search engine.

6. Visit the site you want it to be the Home page

Safari > Preferences > General > Homepage

Click the button “Set to Current Page” button.

7. Restart the Mac.

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Answer 3

Mar 3, 2017 5:45 PM in response to Eric Root

This worked. Thank you. Website now viewable.

From Global Sign website at https://support.globalsign.com/customer/portal/articles/1353318

OS X 10.12 Sierra

To delete both OCSP and CRL cache in OS X 10.12, open a terminal and run the following command:
sqlite3 ~/Library/Keychains/*/ocspcache.sqlite3 'DELETE FROM ocsp;'

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Answer 4

Eric Root

Level 10

685,221 points

Mar 4, 2017 6:58 AM in response to Michael Vallance

You are welcome. Good.

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