Using Mailx to send to list of email addresses

Im trying to use a shell script to send to a list of email addresses in a txt file. Here is what i have tried but it keeps sending to dead.letter...

Success.ksh contains...
mailx -s"Night Batch Success" 'cat /Scripts/email_addresses.txt' < /Scripts/email_body_message.txt

The email body message is working but i cant get the email addresses to work.
I could use some help....Any Ideas?

You should have backticks (ASCII 96) around the cat command.