(2017-02-13, 6:22 am)ファブリス Wrote: Pretty much just using sendmail from php. I have never looked into the CPanel for that. Could there be some settings there that affect the way emails are sent?
Never used Hostgator's CPanel, so I don't know, but it's definitely possible. Email sending has lots of things that can be configured (from basic matters like proper domain name configuration to more advanced topics like DMARC, SPF, DKIM...) hence it'd make sense to look there, but I'd do it only after you really know what's going on with your mail delivery.
(2017-02-13, 6:22 am)ファブリス Wrote: Do you think switching to https will change the way emails are flagged?
Not sure what you mean by "switching to https". If you're talking about your near future plan to switch the entire web server to https, I don't think that would affect your mail in any way (but, then again, mail is more complex than it seems, so getting better "overall score" for your server -if that even makes sense- wouldn't hurt).
If you are talking instead about using cyphered (i.e. TLS) connections to deliver mail to the users' MTAs, that would likely help (but anyway that's something that depends on how every MTA out there likes to be contacted from you, so...)
As you know, spam flagging is usually based on score
, so anything you can do to get the score up, like implementing TLS, SPF or the like (which can require some setup about certificates, email headers, DNS records, etc.) would be of use; but it's usually more important to have "blocking" things sorted out first
: having a properly configured /etc/hosts, for example, can help with some issues if your mails look like they are being sent from "localhost" instead of "koohii.com".
IMO The best you can do is grab one of your flagged emails from the spam folder in gmail (or another similar provider) and inspect carefully all its headers (gmail, at least on its web interface, now has some sort of diagnostics when you press on the message's "show original" option) to put you on the right track about what you should debug first.