No source contemporary with Attila names his birthplace. He is generally placed within Hunnic-controlled territory north of the Danube, in the Pannonian steppe, but no specific site is attested.
What would resolve this A surviving contemporary source naming Attila's birthplace; none of the Greek or Latin accounts of his life (transmitted through Priscus) records where he was born.
OpenHunnic and late Roman/Byzantine history; archaeology of the Pannonian steppeWikipedia