Why does my browser indicate that LastPass has an invalid or expired security certificate?
Below are a few things you can try to resolve this issue.
Verify that your computer's time and date is set correctly
Most certificate warnings are caused because your computer's clock is not set correctly. Verify that your clock is set to the correct day, month, and year.
Check whether your security certificate settings were changed by your employer
Many employers change standard certificate settings within their organization to ensure greater control over what sites employees visit, and in some instances, to monitor all HTTPS traffic. Please check with your IT or network administrator to determine if your default certificates have recently been modified.
Install GlobalSign root certificates (if allowed)
If you're the administrator, you can install the required GlobalSign root certificates (R1 and R3) at https://support.globalsign.com/customer/portal/articles/1426602-globalsign-root-certificates.