Possible reasons for the error are: incorrect mirror specified; mirror is not available (possibly due to an unreliable network connection); mirror is broken (for example because an invalid Release file was found); mirror does not support the correct Debian version.
Ssebbat ahat n tuccḍa d: tisit tarameɣtut i d-yettufernen; tisit ulac-itt (ahat ssebba n yir tuqqna n uzeṭṭa); tisit terreẓ (d amedya acku yettwaf ufaylu Release arameɣtu); tisit ur tsefrak ara lqem n Debian ameɣtu.