I have setup a custom domain (say mydomain) and a mail server for the domain name. Its a plain smtp/pop server (apache james). I am able to send messages to yahoo/gmail/ .... etc. however im unable to receive mails incoming to mydomain from yahoo. All yahoo messages get bounced back.
I don't know what can be wrong. I have not configured SPF and DKIM as I doubt that is mandatory. Im able to receive email from Gmail though.