Dear Clients,
In an effort to reduce the amount of spam delivered to their customers the popular email hosts are willing to toss out a lot of legitimate email. In order to meet Customer's demands for better anti-spam protection for their inboxes, free email providing hosts are finding the high costs of processing millions of spam emails per day intolerable. As a result, several large email hosts like YAHOO have instituted anti-spam policies (sometimes referred to as Greylisting) that stop deliveries of emails from IP addresses that send a large number of messages to their servers in a specified period of time. The period of time and what is considered a "large number" varies, depending upon the host and this information is not published. The spam prevention measures of the large mail providers have reached such levels that if you are sending more than just a few messages to them, your mail server's IP will likely be greylisted. The email services which are using virtual domains on shared IPs, find their mail server IPs unduly targeted for greylisting. It does not matter that our customers are sending legitimate mails; the large mail hosts are still flagging it as spam. This is a problem affecting all companies that send a large number of messages to @yahoo.com, @aol.com, @msn.com, @hotmail.com, and similar email accounts - not just TechnoDG - and no one has a sure-fire solution.
All we can suggest you is to wait for couple of hours when the greylisting would automatically get removed from the IP and your mail would be automatically tried from our wait queue and get delivered.