Synchros must be successfully summoned. A Solemn Judgement will stop you from being able to bring them back since it negates the summon. On the other hand, a bottomless trap hole will remove it from play. Afterwards, you can use Burial from a different dimension to put it back in the grave and then use monster reborn. Cards like Bottomless work after a monster is summoned instead of negating it entirely.
so if a monster lets say like stardust dragon was destroyed by battle, it could be brought back with a monster reborn. But if the stardust dragon was sent there because the summon was unsuccesful due to a card effect such as solemn judgement or black horn of ? (negate special summon of a monster or something along those lines) ten it cant be monster reborned?