Hi There!
We have had a problem on and off for about 12 months with our emails to xtra.co.nz addresses going into their spam filter.
We can't work out why, we aen't on any blacklists we can find, and have changed ip's a few times over that period of time, so I don't think it's IP specific. Our reverse dns matches as does our smtp servers banner.
How can I determine the cause so I can resolve it?