Hi Friends
Sendgrid SMTP mail servers in WHM/cPanel – SMTP stand for Simple Mail Transfer Protocol. Some time your VPS or dedicated server blocked SMTP for some reason and your cPanel SMTP servers stoped.  That’s the reason your all email stuck in Mail Queue Manager. You are obviously here because you want to learn how to configure your Cpanel/WHM managed domain to use SendGrid’s SMTP mail servers. Just follow these easy steps and you will be on your way in no time.

Whats is SMTP?

The Simple Mail Transfer Protocol (SMTP) is a communication protocol for electronic mail transmission. As an Internet standard, SMTP was first defined in 1982 by RFC 821 and updated in 2008 by RFC 5321 to Extended SMTP additions, which is the protocol variety in widespread use today. Mail servers and other message transfer agents use SMTP to send and receive mail messages. Proprietary systems such as Microsoft Exchange and IBM Notes and webmail systems such as Outlook.com, Gmail and Yahoo! Mail may use non-standard protocols internally, but all use SMTP when sending to or receiving email from outside their own systems. SMTP servers commonly use the Transmission Control Protocol on port number 25. SendGrid SMTP mail servers provide services

SMTP is one of the most common and popular protocols for email communication over the Internet and it provides intermediary network services between the remote email provider or organizational email server and the local user accessing it.

Let’s get Started

Login to your WHM account

Click on Service Configuration -> Exim Configuration Manager

Sendgrid SMTP mail servers in WHM/cPanel

Click on the Advanced Editor tab

Find the section called Section: AUTH and paste the following into the text box, substituting in your SendGrid username and password:

driver = plaintext
public_name = LOGIN
client_send = : [YourSendGridUsername] : [YourSendGridPassword]

Find the section called Section: PREROUTERS paste the following in the textbox, substituting in your Domain name in the sender’s line:

driver = manualroute
domains = ! +local_domains
senders = *@
transport = sendgrid_smtp
route_list = "* smtp.sendgrid.net::587 byname"
host_find_failed = defer

Find the section called Section: TRANSPORTSTART and paste the following in the textbox:

driver = smtp
hosts = smtp.sendgrid.net
hosts_require_auth = smtp.sendgrid.net
hosts_require_tls = smtp.sendgrid.net

How to Solve Exim mail bounce back – retry time not reached