According to the author of the book of Nehemiah, some people came back to their homeland from faraway places, but they couldn't prove that they belonged to the families of Israel. This meant they didn't have the special papers that showed they were part of the big family of God's people.
Nehemiah 7:61: And these [were] they which went up [also] from Telmelah, Telharesha, Cherub, Addon, and Immer: but they could not shew their father's house, nor their seed, whether they [were] of Israel. [seed: or, pedigree]
This verse lists the returnees from Babylon, similar to Nehemiah 7:61, but with slight differences in names and numbers of the people and places mentioned.
Ezra 2:59: And these [were] they which went up from Telmelah, Telharsa, Cherub, Addan, [and] Immer: but they could not shew their father's house, and their seed, whether they [were] of Israel: [Addan: also called, Addon] [seed: or, pedigree]