DOMAIN_NOT_RESOLVED, but only when I send mail via a certain method

DOMAIN_NOT_RESOLVED, but only when I send mail via a certain method

So I have a script to send an alert mail. (For smartd) Now, if I run this script manually, the mail sends just fine, but if I let the service run it (I made sure to test with the same user) it doesn't work.

  • verbose output from the "mail" command from when I manually ran the script: LINK
  • verbose output from the "mail" command from when I let the service run the script: LINK
  • the actual script that I'm running to send the mail: LINK
  • my smartd.conf: LINK (line 24 is the only part that isn't a comment)
  • my ssmtp.conf: LINK
  • the mail I get a while after the service tries to send anything: LINK
Anyone have any ideas?