Might be an issue with the MIME-types of the website/webserver.
Had an issue with Genesys Administrator looking similar to yours when someone had been messing around trying to add a new MIME-type to the website/webserver(IIS).
However during that process an unwanted entry was left in the Web.config file of the Genesys Administrator website(ex <mimeMap fileExtension=".XYZ" mimeType="text/plain" />) which caused a conflict with a parent MIME-type. This conflict caused all the MIME-mappings for the website to fail and therefore the webserver didn't know how to serve any of the filetypes(images not loading etc)
In my case Genesys Administrator started working properly as soon as I removed the unwanted entry from the Web.config file.
It might not be the exact same problem for you, but I would consider looking into possible issues with the MIME-types.