Does anyone here know how I can find out what is blocking an email from getting to a host? If I do a simple PHP based mail(firstname.lastname@example.org) it arrives at my gmail-account, but not on other domains nor to some gmail accounts.
I've installed postfix and spamassasin, could these be blocking anything?
My php.ini setting is the default sendmail -t -i.
My concern now is that many of my forum members (vBulletin) complains that they are not receiving their subscription emails after my migration to new servers (still same ISP and all).