Forbidden

I need some help ive been using your WP-DownloadManager for a while now although im new to wp found it very easy to use which for me is great ,now i have a small problem ive uploaded lots of files for download on my dj page found here http://djklass-a.co.uk/ but when i try to create another link after the file is on my server i get a error well not a error more so a FORBIDDEN message can you help me out what have i done i have all the updates and ive not changed anything script wise need some help

https://ww.wp.xz.cn/plugins/wp-downloadmanager/