SMTP relay test script

relaytest.sh

#!/usr/bin/env bash
## Version 1.0.2

my_email_body="Test from telnet"
mail_server_ip="127.0.0.1"
mail_server_port="25"
recipient="sryan@example.com"
sender="\"Ubuntu Server\"<ubuntu@example.com>"

nc ${mail_server_ip} ${mail_server_port} << EOF
ehlo example.com
mail from:${sender}
rcpt to:${recipient}
data
From:${sender}
To:${recipient}
subject: Telnet test
${my_email_body}
.
quit
EOF

This don't work anymore i get:
550 5.5.1 Protocol error
554 5.5.1 Error: no valid recipients

For few days it worked.