"AddTrust External CA Root" Certificate Expired: Websites Won't Open
Hello!
My specs:
Model Name: MacBook Pro (Retina, 15-inch, Mid 2014)
Model Identifier: MacBookPro11,3
OS X El Capitan, v10.11.6
Over the last few days, certain websites will not open on Safari or Opera. The 'error' message states the following:
This Connection Is Not Private
This website may be impersonating “xyz.com” to steal your personal or financial information. You should go back to the previous page.
Go Back
Safari warns you when a website has an expired certificate. This website’s certificate expired 3 days ago. This may happen if the website is misconfigured, an attacker has compromised your connection, or your system clock is incorrect. Your system clock is set to Tuesday, June 2, 2020. If this is not right, fixing the clock may address this warning.
To learn more, you can view the certificate. If you understand the risks involved, you can visit this website.
The culprit seems to be 'ADDTrust External CA Root' certificate expired on 5/30/2020. All the websites that aren't opening point to the 'ADDTrust External CA Root' certificate.
Are there any solutions other than upgrading to Catalina? Can certificates be updated?
Thank you in advance for your help or time.
MacBook Pro 15″, OS X 10.11