To send and receive encrypted emails using Microsoft Outlook 2016 and Microsoft Outlook 2019, do the following:
Open Microsoft Outlook.
Click File at the top of the menu bar and select the Account Settings button under Account Information.
In the E-mail tab, select the desired account and click Change....
In the Account type field, check whether you have set up an IMAP or a POP3 account.
Go to More settings.
Switch to the Advanced tab. Activate the Server requires an encrypted connection (SSL) option.
Then make sure you enter the following settings in the Server Port Numbers section:
IMAP Server Settings
|Server Port Numbers
|Incoming mail server (IMAP)
|Outgoing mail server (SMTP)
If you receive error messages when sending email using port 465, change the Outgoing mail server (SMTP) port to 587 and make sure the connection type is set to TLS. Then, test the settings again.
To complete the process, click OK.
SSL encryption is now enabled for sending and receiving emails