I'm getting a page not found error when trying to visit my custom form This is the form that I created using Drupal 8:

namespace \Drupal\lookup\Form\lookupForm;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

class lookupform extends FormBase
{
    /**
     * {@inheritdoc}
     */
    public function getFormId()
    {
        return 'lookup_form';
    }

    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state)
    {
        $form['Username'] = [
            '#type' =&gt; 'textfield',
            '#title' =&gt; t('ULM Username'),
        ];

        $form['actions']['submit'] = [
          '#type' =&gt; 'submit',
          '#value' =&gt; $this-&gt;t('Save'),
          '#button_type' =&gt; 'primary',
        ];

        return $form; 
    }

    /**
     * {@inheritdoc}
     */
    public function submitForm(&amp;$form, FormStateInterface $form_state)
    {

    }

}




Routing file: 

user.form: 
 path: '/lookupForm'
 defaults: 
   _title: 'Lookup User Autocomplete'
   _form: '\Drupal\lookup\Form\lookupForm'
 requirements: 
   _permission: 'access content'


Info file: 

name: Form 
description: This is a form.
core: 8.x
package: Custom
type: module


I am getting a page not found error. What could be the issue?
Problem 1: Incorrect namespace. The class name should not be included in the namespace. Your namespace should be:

Drupal\lookup\Form

Problem 2: The name of your class is not the same name as the routing file (capitalization).

Class name: lookupform

Routing file: _form: '\Drupal\lookup\Form\lookupForm'

(Capital F)

Problem 3 (credit: laymannx) - you're visiting the wrong path. Should be visiting /lookupform (after fixing the above problems).