#Entering the following command into the terminal –
1) Install sendmail
sudo apt-get install sendmail
2) Configure sendmail
Enter the following command into the terminal and type “Y” for each question it asks –
sudo sendmailconfig
3) Edit hosts file
sudo nano /etc/hosts
Add/Edit the following line to your hosts file and save it-
127.0.0.1 localhost localhost.localdomain YOUR_DOMAIN.com
4) Restart apache
Let’s restart apache –
sudo service apache2 restart
Hope it works’s on your Ubuntu 14.04/16.04.