App Proxy downloading file instead of rendering liquid

I'm building an embedded app and trying to get the App Proxy option to render a liquid page to work. I have set up the proxy correctly in the app, and have the file returning a "Content-Type: application/liquid" header, but when I access the page in my test store, it simply downloads the file.

I'm using laravel-shopify from this repository I have setup correctly app proxy in shopify but problem is that always download the proxy file

I host my project in a Digital Ocean Server

Any idea, thanks a lot !

Here's the original contents of the public/.htaccess file laravel:

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
      Options -MultiViews -Indexes
    </IfModule>

    RewriteEngine On

    # Handle Authorization Header
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

    # Redirect Trailing Slashes If Not A Folder...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} (.+)/$
    RewriteRule ^ %1 [L,R=301]

    # Handle Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]
</IfModule>

via Chebli Mohamed