systemd (OnFailure) using ssmtp with gmail can't send mail

Some important service: [Unit] ... OnFailure=status-email@%n.service

-email@.service

: [Unit] Description=status email for %i to user [Service] Type=oneshot ExecStart=/usr/local/bin/systemd-email.sh %i User=root Group=systemd-journal [Install] WantedBy=multi-user.target I'm getting error

-email.sh: ssmtp: Cannot open smtp.gmail.com:587

I can send mail manually

./systemd-email.sh $RECIPIENT $SERVICE_NAME

It's also working as cronjob. My

/etc/ssmtp/ssmtp.conf

: root= mailhub=smtp.gmail.com:465 FromLineOverride=YES AuthUser= AuthPass= UseTLS=YES Why cron can send mail in this setup but systemd cannot?