Calendar error message: "Calendar can't verify the identity of the server ..."

Hi, I'm repeatedly getting an error message (actually two at once) in Calendar (11.0 - MacOS Big Sur) that says, "Calendar can't verify the identity of the server "apidata.googleusercontent.com".

I click on "Show certificate" and get a note in red that says the certificate ".safezone.mcafee.com does not match input." It then gives a bunch of details on the certificate, none of which give me any indication as to whether the certificate is safe or not. (See image below.) Interestingly, yesterday i was getting the same error message, but referencing a different certificate - one having to do with vail resorts.

The only way to make it go away is to close Calendar. When I open it again, they come right back.

My question is two-fold: Is there anything to worry about here and how do I get the message to go away?

Here's (most of) the complete error message.

Thanks in advance for any help.