As the error was finished because of the god Indra, he grants Hanuman a wish that his human body could be as robust as Indra's Vajra, Which his Vajra may also not hurt him. In addition to Indra other gods have also granted him wishes: the God Agni granted Hanuman https://mahavidya48271.digitollblog.com/36832373/indicators-on-hanuman-you-should-know