When choosing to send an email directly from a Contact record in Daylite, the Daylite Mail Assistant will respect your Apple Mail Preference settings for "Composing".
Options are to send new messages from a specific email address, or account of a mailbox selected.
If you have multiple email accounts added to Apple Mail, emails sent from Daylite will go out from the account you’re currently in. Make sure you have the correct email account selected in Mail at all times.
If the option to automatically select an account for sent emails is enabled in Mail settings, notifications from Daylite will be sent from the email account you’re currently in.
Email accounts can also be selected manually right in the email compose window: