I am using mail via postfix and horde, with users synced to an MS AD server. Using mail through horde works fine, and I have set the server up to relay through sendgrid which is also working well.
The problem I have is that no users can authenticate directly to the server via SMTP to send a mail (using port 587). The TLS handshake works ok, but it always returns authentication failed. I have tried using the email address and login as the username, but nothing seems to work.
I need this to be able to have service accounts forwarding emails (for RAID failures, IDS notifications, etc). It doesnt make sense that horde worked out of the box yet SMTP through postfix doesnt.
Help pls? Am running 4.4-4 errata499 (Blumenthal)