sahilsaid

I found the issue.

It was due to updating this plugin to the latest version. Seems like the latest version is not compatible with wordpress 3.9.2

I downgraded this plugin back to Version 1.3.0.3 and everything is working fine now.

I have fixed this problem by adding the dynamic featured image meta key into allowed types for JSON API with the filter ‘rest_api_allowed_public_metadata’. I used the code below.

function custom_rest_api_allowed_public_metadata( $allowed_meta_keys )
{
    // only run for REST API requests
    if ( ! defined( 'REST_API_REQUEST' ) || ! REST_API_REQUEST )
        return $allowed_meta_keys;

    $allowed_meta_keys[] = 'dfiFeatured';

    return $allowed_meta_keys;
}

add_filter( 'rest_api_allowed_public_metadata', 'custom_rest_api_allowed_public_metadata' );