applyStore] The specified Store cannot be found

I'm going through a Sencha tutorial and I'm receiving this error when attempting to implement a store in my app. I'm sure this is something simple I'm overlooking but I'm having trouble figuring out what it is.

applyStore] The specified Store cannot be found

Here is the relevant code:

//from app.js

stores: [
  'MyStore'   
],


//from the view
Ext.define('listerApp2.view.Main', {
    extend: 'Ext.dataview.List',
    xtype: 'main',
    requires: [
        'Ext.TitleBar',
        'listerApp2.store.MyStore'
    ],
    config: {
        title: 'My listing',
        store: 'MyStore'   
    }
});

//from the store
Ext.define('listerApp2.store.MyStore', {
    requires: ['listerApp2.model.MyModel'],
    
    config: {
        autoload: true,
        model: 'MyModel',
        storeId: 'MyStore',
        alias: 'store.MyStore',
        data: [
            {firstName: 'Washington', lastName: 'George', age: 250},
            {firstName: 'Lincoln', lastName: 'Abe', age: 200},
            {firstName: 'Clinton', lastName: 'Bill', age: 60}            
        ],
        proxy: {
            type: 'localStorage'
        }
    }
            
});
//and the model
Ext.define('listerApp2.model.MyModel', {
    extend: 'Ext.data.Model',
    
    config: {
        fields: [
            { name: 'firstName', type: 'string' },
            { name: 'lastName', type: 'string' },
            { name: 'age', type: 'int' }
        ]
    }
});

You have mixed up many things in your code. For e.g. you have used localStorage and storeId which are not making any sense here. I have simplified your code and pasting here:

Model

Ext.define('MyApp.model.DataModel', {
extend: 'Ext.data.Model',

     config: {
        fields: [
            { name: 'firstName', type: 'string' },
            { name: 'lastName', type: 'string' },
            { name: 'age', type: 'int' }
        ]
    }
});

Store

Ext.define('MyApp.store.DataStore', {
 extend: 'Ext.data.Store',
    config: {
      model: 'MyApp.model.DataModel',
      autoLoad: true,

      data: [
            {firstName: 'Washington', lastName: 'George', age: 250},
            {firstName: 'Lincoln', lastName: 'Abe', age: 200},
            {firstName: 'Clinton', lastName: 'Bill', age: 60}            
        ]
  }
}); 

View

Ext.define('MyApp.view.HobbyList', {
    extend: 'Ext.List',
    xtype: 'hobbyList',
    requires: [
    'Ext.dataview.List'
    ],
    config: {
        styleHtmlContent : true, 
        itemTpl : new Ext.XTemplate(
            '{firstName} {lastName} is {age} years old.'
            ),
        store: 'DataStore'
    }
}); 

I have tested this. It is working fine. Take a look.

Happy Coding!