Large (zip/ftf) files can't be downloaded "directly"?

I’ve got a problem with wp-filebase (pro).

If a user tries to download a file bigger 1GB from my website ( http://leetbox.net ), the download stops at about 1GB with “unknown network error”.

fpassthru is activated and i’ve seen an equal issue with the free plugin on a blog from a friend (smaller files with about 300-400mb / .mp3).

Kind regards
meet

https://wordpress.org/plugins/wp-filebase/