Site Feed Settings - Choose Full

To make sure that all of your Blogger theme widgets function properly, such as the Featured Slider, you need to check that your site feed is set to Full. Here's what you need to do:

1. From your Blogger dashboard, go to Settings.
2. Scroll down to the Site feed section.
3. Click on the Allow blog feed.
4. This will reveal a window with additional settings > choose Full. 
5. Click Save to apply the changes. 

Note: In case your widgets still don't appear, please also verify that your blog is not set to 'Private' in the same Settings page.