Failed to load HTML file (13 replies)

after the update to 2.3.0 I get these errors:

Failed to load HTML file: Please check your server configuration. You may want to whitelist "*.html" files from the "plugins" directory. The HTTP status code is 404 for URL "plugins/ZenMode/angularjs/quick-access/quick-access.html"

Failed to load HTML file: Please check your server configuration. You may want to whitelist "*.html" files from the "plugins" directory. The HTTP status code is 404 for URL "plugins/CoreHome/angularjs/enrichedheadline/enrichedheadline.html"

Failed to load HTML file: Please check your server configuration. You may want to whitelist "*.html" files from the "plugins" directory. The HTTP status code is 404 for URL "plugins/Feedback/angularjs/ratefeature/ratefeature.html"

The changing of the directories permissions doesn't fix the problem.

My server error log doesn't contain any error messages.

htaccess file:

# First, deny access to all files in this directory
<Files "*">
<IfModule mod_version.c>
<IfVersion < 2.4>
Order Deny,Allow
Deny from All
</IfVersion>
<IfVersion >= 2.4>
Require all denied
</IfVersion>
</IfModule>
<IfModule !mod_version.c>
<IfModule !mod_authz_core.c>
Order Deny,Allow
Deny from All
</IfModule>
<IfModule mod_authz_core.c>
Require all denied
</IfModule>
</IfModule>
</Files>
# Allow to serve static files which are safe
<Files ~ "\.(test\.php|gif|ico|jpg|png|svg|js|css|htm|html|swf|mp3|mp4|wav|ogg|avi)$">
<IfModule mod_version.c>
<IfVersion < 2.4>
Order Allow,Deny
Allow from All
</IfVersion>
<IfVersion >= 2.4>
Require all granted
</IfVersion>
</IfModule>
<IfModule !mod_version.c>
<IfModule !mod_authz_core.c>
Order Allow,Deny
Allow from All
</IfModule>
<IfModule mod_authz_core.c>
Require all granted
</IfModule>
</IfModule>
</Files>