Wordpress Gutenberg block

I have a problem with a custom block which send me an error when I reload the edition page.

I don't understand what the problem is. In regards of the error, actual and expected are the same.

Here the error :

Block validation: Block validation failed for namespace/nottomiss ({object}).

Expected:

<div class="wp-block-utopiales-nottomiss"><p>label test</p><p>label test</p></div>

Actual:

<div class="wp-block-utopiales-nottomiss"><p>label test</p><p>title test</p></div>

Here my code :

const { registerBlockType } = wp.blocks;
const { __ } = wp.i18n;
const { PanelBody, TextControl } = wp.components;
const { BlockControls, InspectorControls, RichText } = wp.editor;
const { createElement, Fragment } = wp.element

registerBlockType( 'namespace/nottomiss', {
    title: __( 'Nottomiss' ),
    description: __('My description'),
    icon: 'star-filled',
    category: 'widgets',
    supports: { align: true, alignWide: true },
    attributes: {
        label: {
            type: 'string',
            source: 'html',
            selector: 'p',
        },
    title: {
        type: 'string',
        source: 'html',
        selector: 'p',
    },
},
edit: function( props ) {
    const { label, title } = props.attributes;

    function onChangeLabel( newLabel ) {
        props.setAttributes( { label: newLabel } );
    }

    function onChangeTitle( newTitle ) {
        props.setAttributes( { title: newTitle } );
    }

    return (
        <Fragment>
            <BlockControls>
            </BlockControls>
            <InspectorControls>
                <PanelBody title={ __( 'List' ) }>
                </PanelBody>
            </InspectorControls>
            <RichText
                identifier="label"
                tagName="p"
                placeholder=""
                value={ label }
                onChange={ onChangeLabel }
            />
            <RichText
                identifier="title"
                tagName="p"
                placeholder=""
                value={ title }
                onChange={ onChangeTitle }
            />
        </Fragment>
    );
},
save: function( props ) {
    const { label, title } = props.attributes;

    return (
        <div>
            <RichText.Content
                tagName="p"
                value={ label }
            />
            <RichText.Content
                tagName="p"
                value={ title }
            />
        </div>
    );
},
} );

Thanks in advance for your answer,

The selectors are how the editor pulls the data from the saved html, and currently your selectors aren't targeting the content. You could change your selectors to something like this:

attributes: {
  label: {
    type: 'string',
    source: 'html',
    selector: '.label'
  },
  title: {
    type: 'string',
    source: 'html',
    selector: '.title'
  }
}

And you could change your save function to this:

save: function(props) {
  const { label, title } = props.attributes

  return (
    <div>
      <div className="label">
        <RichText.Content
          value={ label }
        />
      </div>
      <div className="title">
        <RichText.Content
          value={ title }
        />
      </div>
    </div>
  )
}