Included in Jaztek's mail services, is an anti-spam measure called greylisting.
Greylisting is a technique used by receiving mail server to delay, for a fixed period of time, the receipt of email from another email server where the originating email address is unknown.
After a fixed period of time, the sending mail server tries again and the email is received by the receiving mail server.
All mail servers are required to retry mail delivery and as such - legitimate email will always be re-delivered to you email. If it is the first email you have received from a particular email address, then there will be a short delay in the receipt of that email. An emails received after that will automatically be delivered to you promptly.
The reason this is an effect anti-spam measure is that spammers send many millions of emails and if at the first attempt the email cannot be delivered, the spammer will usually not retry the mail delivery.
You can find more information about greylisting at http://en.wikipedia.org/wiki/Greylisting
Grey listing is a service offered on all accounts. Further anti-spam and anti-virus protection is available with our Mail Guard service.