Is it illegal to send short messages about real estate sales?

Illegal acts are also called "invalid acts". An illegal act. Acts that violate the law. Different from the objective illegal behavior, the actor is subjectively at fault when carrying out the behavior, thus infringing on the social relations protected by law. Subjective fault refers to the subjective state of intention or negligence. According to the nature of illegality, illegal acts can be divided into criminal violations, civil violations, economic violations and administrative violations. According to the degree of harm to society, illegal acts can be divided into general illegal acts and serious illegal acts (crimes).