How to get png attachment to work on my Jira Cloud App?

Hi,

On my Jira Cloud App png image attachment of Jira Issues do not work.

I thinks problem is in my .htaccess file that is below:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d 
RewriteRule ^.*$ - [NC,L]
RewriteRule ^.*$ index.php [NC,L]

Here is a error as a Mock-up:

How to fix this issue?