Unfortunately no warranty. Is there any way to fix it by my self
If this happened right after a bios flash on a fully working card, its a bios issue and can be fixed by reflashing the correct bios.
If you had been using the card and it was working fine, and one fine day it stopped working then the card has gone bad which happens to Rx 470/480/570/580s a lot (about 10% failure rate over time). Theres nothing you can do to fix it.