Enter your macOS login password, then click the Always Allow button so that the OS will remember your decision. The first time you sign a message in Outlook with a private key installed in Keychain Access, macOS will prompt you for permission.
To exchange public keys with another person, simply exchange signed, unencrypted email messages. If you try to send an encrypted message to an email address that you do not yet have a public key for, Outlook will present a warning dialog allowing you to send the message unencrypted.If you want to change the digital signature and encryption settings for the message, select the Options tab, then use the Encrypt and Sign buttons to toggle these features on and off.Note that if you set your preferences to sign email by default, you will see a message saying that “This message will be digitally signed.”
This means, that if you are still using this version of Outlook, you will need to upgrade your.
If you are signing with a Business Identity certificate on a YubiKey, you will need to install a separate S/MIME certificate for encryption.
For most users, you can use the same certificate you selected for signing.
This new Outlook for Mac uses Microsoft sync technology that already powers Outlook for iOS and Android and Windows Mail app.
Way back at Ignite 2019, Microsoft announced an all-new Outlook for Mac experience with redesigned UI, improved performance and several new features.