All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Hajj is an obligation on a person who is able to perform it as Allaah Says (what means): {And [due] to Allaah from the people is a pilgrimage to the House - for whoever is able to find thereto a way.}[Quran 3:97]
As regards a person who is unable to get a visa or he is prevented from travel, then he is unable to perform Hajj and he is not sinful if he did not perform it because he is unable to do so. Hence, Hajj is not an obligation on him as long as he cannot find a way to perform it. This does not only apply to Hajj, but a person is not obligated to perform any matter he is unable to do as Allaah does not burden a soul more than it can bear.
Allaah Knows best.