Subscription does not exist of type "Subscription"

I am new to angualr 2. And I am making a small application for practice. I have a service to authenticate users when they login. And here is the login function.

login(email:string, password:string){

        var loginrul="https://filing.herokuapp.com/api/v1/auth/login/";
        return this.http.post(loginrul,JSON.stringify({  password: password,email: email }),
            {headers:new Headers({'Content-Type':'application/json'})}
            ).map(res=>res.json()).
            subscribe(
                data => localStorage.setItem('id_token',data.auth_token),
                error=>console.log(error)
            );
    }

      

        
        
        
      

    

When I call this function in the angualr component, it throws the error "Subscription signature does not exist in type Subscription."

doLogin(event) {
        console.log(event);
        console.log(this.loginForm.value);


        let formData = this.loginForm.value;
        let email = this.loginForm.controls.email.value;
        let password= this.loginForm.controls.password.value;
        this.auth.login(email,password).subscribe(res =>{
            console.log(res);
            if(res.status===200){
                this.router.navigate(['dashboard']);
            }
        }
        )
    }

      

        
        
        
      

    

I think why angular is giving this error is because I am using subscription in the login function as well as when calling the login function. Please suggest some solution or alternative approach to achieve the result I am trying to achieve in the login function.