Calendar can't verify identity of the server P35-caldav.icloud.com

Hey Slowlyan,

Thanks for using Apple Support Communities! It looks like no one has responded to your question. Here are a couple things that might help others answer your question:

What is the exact wording of the error you're seeing?

Is this error happening when trying to open Calendars, perform a specific task, or something else?

Did you recently make any changes to your Mac, or Calendar?

Thanks again, and have a great day!

The error I'm getting is similar: Calendar can't verify the identity of the server "caldav.aol.com" The certificate for this server is invalid. You might be connecting to a server that is pretending to be "caldav.aol.com" which could put your confidential information at risk.

I made no changes to my MAC. Just updated operating system and started getting this and other error messages.

I am getting this too. The exact wording of the message is (which, annoyingly, is disabled for copy and paste):

Calendar can't verify the identify of the server "p35-caldav.icloud.com".

The certificate for this server is invalid. You might be connecting to a server that is pretending to be "p35-caldav.icloud.com", which could put your confidential information at risk.