Proper way to get array from session

This will return null because there is no matching data.

You cannot get the data using:
session('error')['meta']['featured_image']
for ['error' => ['meta.featured_image' => '...']]

the input I have is this:

PHP Code:

<input type="file" id="featuredImage" accept=".png, .jpg, .jpeg" name="meta[featured_image]"> 


I guess session('error.meta.featured_image') should be correct?