Apple mail on Beta - 4
Using a Gmail account that is synced using iCloud syncing. On just one Mac I keep getting asked to add the password, and when I say yes, the Internet accounts pat of System Preferences comes and and then shows me a message
"Connection Insecure
Failed to verify the server certificate. This could be because of your network configuration or your proxy settings."
But it works fine on other machines, and on my iOS devices.