Can the server block executable files from uploading even if you allow them in wordpress?

I use the plugin File Upload Types to allow the uploading of exe and svg files. I can upload svg’s now but not any exe files. It says:

Unexpected response from the server. The file may have been uploaded successfully. Check in the Media Library or reload the page. 


https://*/wp-admin/async-upload.php 403 (Forbidden) 

Any idea what is going on? I can upload the file with FTP and it stays there. I need to upload these files because I want to offer my application for download.