Regenerate Root CA Certificates using Admin UI
It is recommended to regenerate the Trusted Root CA certificate file using Admin UI. To do that open Admin UI / Squid Proxy / HTTPS (SSL) / Trusted Root Certification Authority . Click on the Generate New Certificate button, fill in all fields as required, scroll down and click the Generate Certificate button.
If you had SSL inspection activated with a different Root CA certificate before, then some generated SSL certificates may have been stored by Squid on disk to speed up SSL filtering. Web UI correctly removes these cached certificates upon generation of a new certificate. No action is required from you.