Does one sin by attempting to speak to someone who ignores them and receives no answer?

It is not permissible for a Muslim to shun his brother for more than three (days), unless there is a legitimate Shar'i reason; based on the saying of the Prophet, peace and blessings be upon him: "It is not lawful for a Muslim to shun his brother for more than three nights. They meet, and this one turns away, and that one turns away. And the best of them is the one who initiates the greeting of peace." So, whoever tries to re-establish connection with someone who is shunning him, and the shunning person does not respond, then there is no sin upon him. Rather, he is the best of those who were shunning each other, and he will be rewarded for that, and the sin remains upon the one who insists on the shunning.