On a simpler level it boils down to this: Jews (except for those who identify as Messianic Jews) reject the idea that Christ was the Messiah prophesised about in the Old Testament.

Me being pedantic here: Replace “Christ” with “the Jesus of the Gospels and Paul’s letters”, and replace “Old Testament” with “late antiquity Jewish writings such as Daniel, and apocalyptic Jewish communities such as those which revere the Book of Enoch.”