
Mail - one of the most important functions of the exchange of information in electronic form of information can disrupt the work of many factors: the wrongly specified non-existent address, a mailbox size limit of the receiver, analyzing your message considered spam it, applied the strict requirements for delivery and dismissed the letter, locked receive mail from your IP address, refused admission because the IP address is in the list of DNSBL, in the body of the message is a virus.