Error loading this resource (MP4 files)

Hello,

We got a multisite wordpress with different sites.
When we upload a mp4 file to it, we keep getting ‘Error loading this resource’ when we open the page. I’ve been looking and looking but can’t find the solution.
The folder /var/www/html/NAME/wp-content/uploads/2016/03/mymedia.mp4 all have apache with 755 as a config so that should be ok.

This is my http conf:
NameVirtualHost *:80

<VirtualHost *:80>
        ServerName bla.bla.ba
        ServerAdmin emailhere
        DocumentRoot /var/www/html/
        ServerSignature off
        <Directory />
                Options FollowSymLinks
                AllowOverride All
        </Directory>
        <Directory "/var/www/html">
            Options Indexes FollowSymLinks MultiViews
            Order allow,deny
            AllowOverride All
            Allow from all
        </Directory>
</VirtualHost>

And this my .htaccess:
(Located in: /var/www/html/NAME )

RewriteEngine On
RewriteBase /NAME/
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

# BEGIN W3TC Browser Cache
<IfModule mod_deflate.c>
    <IfModule mod_headers.c>
        Header append Vary User-Agent env=!dont-vary
    </IfModule>
        AddOutputFilterByType DEFLATE text/css text/x-component application/x-javascript application/javascript text/javascript text/x-js text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/json
    <IfModule mod_mime.c>
        # DEFLATE by extension
        AddOutputFilter DEFLATE js css htm html xml
    </IfModule>
</IfModule>
# END W3TC Browser Cache

Anyone got an idea?