SO, I am sending email from Zimbra like a champ.
But I am having difficulty with one form of email address.
I have an address of the form firstname.lastname@example.org
But the mail keeps getting defered. I know I can send using a different SMTP server. Here is the info from my log:
May 22 13:24:14 zimbra postfix/qmgr: 2A69417E01E3: from=<email@example.com>, size=1229, nrcpt=1 (queue active)
May 22 13:24:14 zimbra postfix/smtp: 2A69417E01E3: host mx02.nic.name[126.96.36.199] said: 451 Spamhaus - IP Lookup (in reply to RCPT TO command)
May 22 13:24:14 zimbra postfix/smtp: 2A69417E01E3: to=<firstname.lastname@example.org>, relay=mx03.nic.name[188.8.131.52]:25, delay=455, delays=454/0.01/0.31/0.14, dsn=4.0.0, status=deferred (host mx03.nic.name[184.108.40.206] said: 451 Spamhaus - IP Lookup (in reply to RCPT TO command))
May 22 13:24:21 zimbra zmmailboxdmgr: status OK