Missing Cron Email When Restarting smtpd

I have a cron job that renews an SSL certificate from Let's Encrypt, and then restarts the smtpd daemon so that the new certificate is picked up. This all works fine--as proven by both the presence of a new, valid cert on disk, and smtpd successfully restarting--but cron never sends an email with the output of the job. What gives?

https://www.packetmischief.ca/2021/02/03/missing-cron-email-when-restarting-smtpd/

#cron #mail #opensmtpd