How can I send an alarm email

[hope1234567hope]

this is mysql config：

• title:monitorThreads
  position: [[0, 32], [80, 12]]
  rate-ms: 1000
  sample: $mysql_connection -e "show status like 'Threads_created';" | awk '{print $2}'
  border: false
  color: 178
  triggers:
  • title: Threads_created
    condition: echo "$cur < 17" | bc -l
    actions:
    terminal-bell: true
    visual: true
    script: |
    echo "alert：Threads_created is ${cur}" | mail -s "alert mysql" hellmail@example.com

But I didn't receive the email，why？？？？This script is not working，how to do？