Unable to Send or Receive Email with Rainloop or mail cmd line
Hello all! I've been using Linux for several years but server administration is fairly new to me, so I decided what better time to learn than now! Anyways I'm trying to set up a mail server and honestly I understand none of this. I have Froxlor (web administration console) installed and it has given me configuration files to use with dovecot/postfix. I can post these if necessary. I also have rainloop installed for my webmail. I can authenticate users, and I can add the domain, and SMTP/POP3/IMAP traffic (appears to be) working. At least the ports are open and rainloop allows me to add my server as a domain (it doesn't add domains to the list of logins if the mail protocols aren't working).
My problem is, I created a user (firstname.lastname@example.org) for test usage and have been able to successfully login to rainloop with its credentials, but when I try to send an email I get a popup from rainloop saying "can't send message.". I've enabled logging on rainloop and the issue seems to stem from a "Temporary lookup failure". I'm completely stumped.
Again, I can post all configs and any logs you may think are relevant. Can anyone help?