Install outgoing email from Debian/Ubuntu system through SendGrid

outgoing_emails_with_sendgrid.sh

$ sudo apt install postfix mailutils  
#   Choose host type 'No configuration'

$ sudo cp /usr/share/postfix/main.cf.debian /etc/postfix/main.cf

$ sudo vi /etc/postfix/main.cf
#  Add lines below
	smtp_sasl_auth_enable = yes
	smtp_sasl_password_maps = static:apikey:paste_your_key_here
	smtp_sasl_security_options = noanonymous
	smtp_tls_security_level = encrypt
	header_size_limit = 4096000
	relayhost = [smtp.sendgrid.net]:587

# Redirect root emails to real email address
$ sudo vi /etc/aliases
   root: [host]_postfix@[your domain]

$ sudo service postfix restart

# Check logs 
$ tail -f /var/log/mail.log