Here is your problem:
Jun 24 12:54:48 amiga postfix/smtp[26534]: connect to mail.'external
host'[external host IP]:25: Connection timed out
Jun 24 12:54:48 amiga postfix/smtp[26534]: 7016C1C80B89:
to=<customer@anywhere>, relay=none, delay=30, delays=0.1/0.01/30/0, dsn=4.4.1,
status=deferred (connect to mail.'external host'[external host IP]:25: Co$
After exactly 30s the connection times out.
Many ISPs do not allow outbound connections to port 25. That is a
fairly standard configuration to block spam from the ISP's customers.
Wietse
