Site certificate error message

[LDB]

Recently I started getting messages from my Kaspersky software about a certificate name error for the site. It happens one time when I click the "new posts" button, if I've been logged off my computer for more than an hour or so. It won't happen again all day long but if I log off and back on it will. I have no clue about it but would love to see it back to the way it was where no message boxes pop up and stop me from proceeding. So far at least it only happens on this site out of the dozen or so I regularly visit.

[EMY92]

I'll pass this along to our server guy to check out. Thanks!

Also, if this happens again, would it be possible to get a screenshot? Thanks