As the error was carried out from the god Indra, he grants Hanuman a wish that his system will be as robust as Indra's Vajra, and that his Vajra can also not hurt him. In conjunction with Indra other gods have also granted him wishes: the God Agni granted Hanuman https://brooksczunh.iyublog.com/36012703/the-definitive-guide-to-hanuman