So im trying to excute this bash script but it keeps telling me that FTP is an Invalid command is the command not supported?

#!/bin/bash
file="$(date +"%y%m%d")-rtu_workspace.7z"
source="/home/user/rtu_workspace"
backupdir="/home/user/Backup/"
usr="USER"
pw="PWD"
host="10.0.1.251"

find $backupdir -mtime +7 -exec rm {} \;

echo "Creating backup of file $file of $source @ $(date) "
7z a -xr\!*.o -t7z $file $source -mx9

echo "Connecting to FTP server $host"
ftp -n -v -d $host << EOF
user $usr $pw
binary
cd /$usr/
put $file
dir
close
bye
EOF

echo "$file uploaded to $host"
echo "Moving file to backup dir $backupdir"
mv $file $backupdir
echo "End of backup @ $(date)"

I know the script works as i've tested it on a regular ubuntu machine; it its not running within terminal on TKL.