We're sending out 1000's of mails per day from our site (mainly "click here to verify your subscription") and too many are getting flagged by spam (mainly hotmail). One of the things I noticed in the headers is
X-Authentication-Warning: srv01.site.com: www-data set sender to
[email protected] using -f
Is this something I should be worried about, that may cause spam flags to raise?
(I'm already checking various issues that have been mentioned regarding spam flagging over at stackoverflow, I know there are many factors in play)