Hello.
It is impossible for the script to download files from an "alien" (not hosting) ftp-server.
Tried through
1) CURL
2) file_put_content + file_get_content
3) copy
4) ftp_get
For some reason, it turns out to download files from an ftp-hosting, but you cannot download from third-party ftp (the script takes about a minute, without errors, and creates an empty file).
Maybe these are some limitations / features on the hosting?