I'm assuming you are the IT administrator for a collection of IT systems. If you run 'certlm.msc' on your Windows 10 machine you will see the Windows certificate management UI.
You will see there is a section called Trusted Root Certification Authorities:
All of these are the "root certificates" your operating system trust. Each certificate authority has one or more root certificates it uses to issue trusted certificates. These certificates (for a website etc) are only trusted by systems which also know about the same "root certificate".
When your operating system trust store is out of date, it will gradually start to no trust various websites.
Your trust store is now out of date and needs to be updated with the latest root certificates.
You can install each one manually, or a way to do this automatically is to enable the windows feature for automatic updates: An automatic updater of untrusted certificates is available for Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2