Email blocking rules.
Electronic mail is arguably the largest and most important service provided by the Internet.
It is also being widely abused to cheaply deliver junk email solicitations to millions of people every day. These tightened policies mean email users, mostly those using desktop mail clients, are more likely to have problems unless they know what policy restrictions are in place and how to deal with these restrictions. The short answer is, because the email servers on UA systems are being abused to send junk email and those receiving this junk email are, rightly, complaining. For those who may need to respond to users' questions, here is an attempt at an explanation that might help. In the last two years, a form of doing business on the Internet has emerged that takes advantage of two features of the Internet.