I have a hostgator VPS account with primary domain primarydomain.com. Under that domain, i created another cPanel account for a sibling domain called siblingdomain.com. The primarydomain.com account is for personal use and siblingdomain.com is where i have xenforo installed (and what i'm trying to get to work! ).
Now, whatever i do - SMTP (using primarydomain and siblingdomain credentials), default (with and without the -f option), SPF enabled, DKIM enabled... i just cannot get a confirmation email to land in a normal inbox - testing is using gmail and hotmail email accounts.
If i look at the email headers associated with the spammed emails they always seem to say hostname "primarydomain.com", and sender domain "siblingdomain.com":
X-AntiAbuse: Primary Hostname - primarydomain.com
X-AntiAbuse: Original Domain - gmail.com
X-AntiAbuse: Originator/Caller UID/GID - [502 501] / [47 12]
X-AntiAbuse: Sender Address Doamin - siblingdomain.com
I'm suspicious that because the primary hostname doesn't match the sender address domain, gmail immediately thinks it's spam. Would you think that's the case? I cannot change the hostname because i have other domains under that VPS account that may get affected as well. Any ideas?