backup on destination ftp without ssl

hello, i need a schedule backup from my virtualmin server on a remote nas ( not managed by me ).

that nas has enabled ftps , but is not configured properly. in fact not working with ftps protocol, but only with ftp ( without ssl )

now i write a script with lftp that backup only mysql db, but i would run "classic" schedule backup form virtualmin. but i got an error

#

Uploading archive to FTP server 1.2.3.4 .. .. upload failed! Failed to connect to 192.168.0.1:50963 : Connection timed out

#

i believe that nas is "natted" and is not configured port forwarding.

i can't manage remote nas, then my only solution ( though is not secure ) is force remote destination backup as ftp without ssl.

Thank you in advance

Alessandro