Why did northerners and southerners reject john crittendens compromise?

Northerners rejected John Crittenden's compromise because it proposed the extension of the Missouri Compromise line, allowing slavery in territories north of the line, which contradicted their anti-slavery stance. Southerners, while initially supportive, ultimately opposed it due to fears that it did not go far enough in protecting slavery in all territories. The growing sectional tensions and the belief that compromises were inadequate to address the moral and political divisions over slavery led both sides to reject the proposal.