Your setter method is returning the wrong value for the major property

class Student {
    constructor(gpa, credits){
        this.gpa = gpa;
        this.credits = credits;
    }

    stringGPA() {
        return this.gpa.toString();
    }

    get level() {
        if (this.credits > 90 ) {
            return 'Senior';
        } else if (this.credits > 60) {
            return 'Junior';
        } else if (this.credits > 30) {
            return 'Sophomore';
        } else {
            return 'Freshman';
        }
    }

     set major(major){
       this._major= major;
       if(this.level=== 'Senior'|| this.level==='Junior'){
         return this._major;
       }else if(this.level=== 'Freshmen' || this.level==='Sophomore'){
         return 'None';
        }
     }

}

var student = new Student(3.9, 60);