As the error was accomplished by the god Indra, he grants Hanuman a desire that his physique can be as powerful as Indra's Vajra, Which his Vajra could also not hurt him. Along with Indra other gods have also granted him needs: the God Agni granted Hanuman a want that https://shanidevtemplenearaustralia.blogspot.com/2025/01/exploring-spiritual-essence-of-hanuman.html