Cant get the plugins I need to load in?

Hello,

I recently purchased a theme and need certain plugins to work and change the theme. I go to my plug ins page where it states exactly what plug ins the theme needs to work so I follow the steps and click install for each but I keep getting the message:

An error occurred while installing Visual Composer Page Builder: Download failed. Filtered.

How do i change the filter to allow these plugins to load??

Please can somebody help!!

Thanks.