I have problem on sending mails with virtualmin, my mails gets into spam or receiver not accepts mail at all. ex yahoo accepts mails, gmail receives as spam and gmx.com returns error like below:
Feb 7 06:44:35 ts1 postfix/smtp[28764]: 2D08260DD5: to=xxxxxx@gmx.com, relay=mx01.gmx.net[212.227.17.4]:25, delay=25506, delays=25505/0.01/0.73/0, dsn=4.0.0, status=deferred (host mx01.gmx.net[212.227.17.4] refused to talk to me: 554-gmx.net (mxgmx112) Nemesis ESMTP Service not available 554-No SMTP service 554 invalid DNS PTR resource record, IP=93.184.xxx.xxx)
I am not sure how to solve this, may be this is IPS problem :S.
Not all mail servers accept mail from dynamic/residential IP addresses, it sounds like you may be running into an issue with that.
They mention that the PTR record (reverse DNS) is the issue – unless your ISP is willing to change that for you, you probably won’t be able to send email directly to some servers.
However, you could always relay your email through your ISP’s mail server, rather than sending email directly.