ngSubmit not working

I have an angular 4 form where I am trying to submit data

HTML Code

<form class="form-horizontal"   [formGroup]="signupForm" 
(ngSubmit)="onFormSubmit()" >
<fieldset>
  <legend>Scheduler</legend>
    <!--- Gender Block -->
    <div class="form-group">
    <label for="scheduleJob">Schedule Job</label>
    <input type="text" formControlName = "schedulejob"
      id="scheduleJob"
      placeholder="Schedule Job">

Button code

 <div class="form-group">
        <button type="reset" class="btn btn-default">Cancel</button>           
        <button type="submit"  class="btn btn-primary">Submit</button>          

    </div>

Scheduler.TS file

import { Component, OnInit } from '@angular/core';
import { Scheduler } from 'rxjs/Scheduler';
/* Import FormControl first */
import { FormBuilder, FormGroup, Validators } from '@angular/forms';

@Component({
  selector: 'app-scheduler',
  templateUrl: './scheduler.component.html',
  styleUrls: ['./scheduler.component.css']
})
export class SchedulerComponent implements OnInit {

  //Gender list for the select control element
 private scheduleTypeList: string[];
 //Property for the user
 private scheduler:Scheduler;

 private signupForm: FormGroup;

 constructor(private fb:FormBuilder) { } 

  ngOnInit() {   

    this.scheduleTypeList =  ['Type 1', 'Type 2', 'Type 3'];
    this.signupForm  = this.fb.group({
      schedulejob:  ['', Validators.required] ,               
      frequency: ['', Validators.required],
      days: ['', Validators.required],
      zone: ['', Validators.required],
      schedulerjobtype:['', Validators.required]
  })  
  } 
  public onFormSubmit() {
    this.scheduler = this.signupForm.value;
    if(this.signupForm.valid) {
        this.scheduler = this.signupForm.value;
        console.log(this.scheduler);
      // alert(this.scheduler);
        /* Any API call logic via services goes here */
    }
    //alert(this.scheduler);
    console.log(this.scheduler);
}
}

Why is the execution not passed to onFormSubmit on submit click and alert or console.log not printing values?

Like I said in the comment, if your button is not inside your form it will not submit it.

So change to:

<form>
  ...
  <button type="submit">Submit</button>
</form>

It is possible however to have it outside if you do it a bit differently, as described in this question.