Certificate is expired or is not yet valid

@XfinityJohnG​ No. It has stopped popping up. I actually never got to see the middle man that was causing issues but I appreciate such a quick response! Thank you!

@AoshiZero​  Other super common reasons for cert errors?  Incorrect computer time, outdated OS (update the cert store in your OS -- apply OS updates when they come out), outdated browser (update those too), hijacked browser redirecting your searches/web traffic to a proxy (common adware exploits).  Outdated bookmarks you saved that will serve up the wrong cert -- those go stale too when a site changes.  All need to be investigated.

Is a "web shield" a good thing or a bad thing?  Depends on who you trust.  If you use Xfinity equipment, the DNS traffic is intercepted and private data is gleaned about your web browsing habits.  If you use a web shield, the DNS traffic is intercepted and private data is gleaned about your web browsing habits, you're just giving the data to someone else.  Depending on the product, some will block data from known compromised sites, and can help with cross-site-script attacks.  Sometimes even can identify incoming "PUPS" -- potentially unwanted programs -- otherwise known as browser exploits.

Better?  Use an OS with user and system privilege separation for web surfing (not windows).  Unix/Linux is better at this.  Mac to some degree, although their products are just as bad as Chrome and Windows as far as privacy goes.  Use features in web browsers.  Use add-on programs such as ad blockers, script blockers, and cookie blockers (tracking protection).  Always stay up-to-date on software.     

I am glad to hear that you are no longer seeing that message @AoshiZero, we hope everything continues to work without issue! If the message pops back up again in relations to Kaspersky and your services continue to work without issue, it may be a good idea to connect with them to ensure everything is set up correctly with them. Please never hesitate to make a new post should you need assistance. Our team and entire community will always be here to help!