Configuration WHM & SendGrid SMTP

SendGrid is everything you need to send emails that cut through the noise and make a connection.

Service Configuration > Exim Configuration Editor -> Advanced Editor

Once you are in the Advanced Editor Locate the section as follows:
Section: AUTH

Within this text box paste the following:

Replace: YourSendGirdUsername, YourSendGridPassword

driver = plaintext
public_name = LOGIN
client_send = : YourSendGirdUsername : YourSendGridPassword

Then locate the next section called:


Within this text box paste the following replace thedomainhere :

driver = manualroute
domains = ! +local_domains
senders = *@thedomainhere
transport = sendgrid_smtp
route_list = "* byname"
host_find_failed = defer

Then locate the next section


Within this text box paste the following :

driver = smtp
hosts =
hosts_require_auth =
hosts_require_tls =


Although this setup and how to was to use and explain how to configure Send Grids SMTP server, it's a starting point for use with other remote SMTP servers, you just need to change the values accordingly.
the outcome was that my clients domain was now using Send Grids SMTP server, whilst the other client hosted domains would continue to use the local SMTP server.