This KB article assumes that an organisation account has been created in Proofpoint Essentials, and a privileged user account exists and is being used to manage this organisation. If you have a question related to POP or IMAP, please see the knowledge base article about that. The steps to start processing inbound email are as follows:

While logged into the user interface, navigate to Company Settings > Domains tab

1. Click New Domain button
2. Enter the domain name 3. Choose Domain purpose.  Management is for solely managing the domain.  This setting will not relay email. Relay is for domains that will be used for email deliver
4. Enter the Primary SMTP Destination IP Address or hostname where we are sending your mail to. Make sure the SMTP destination can receive email via port 25 and accept email for your registered domain. 5. Add SMTP Failover 1, 2, 3, 4 IP addresses (Optional)
6. Pick a verification method TXT record META tag
7. Click Verify Later if you need to wait for DNS propagation for TXT record or META tag to get added. This will save the settings with verification codes If ready you may use Verify Now. (Once META tag is added to website or TXT record is ready) 8. If Verify Later was used come back Domain settings when DNS has propagated 9. Once DNS has propagated for TXT record Click Verify Now
10. Enable relay but using the toggle switch

Important Note: Remember that changes here take place every half hour. (Top and bottom of the hour)

Additional Information:  These steps are also located in the Getting Started Guide

[Setup Step 1] - Current Step - Instructions for activating Proofpoint Essentials for a domain's inbound email

[Setup Step 2] - Creating Users

[Setup Step 3] - Firewall lockdown options for Email & LDAP Discovery

[Setup Step 4] - Instructions for changing MX records

[Setup Step 5] - (Optional): Instructions on activating Proofpoint Essentials for an organization's outbound email

[Setup Step 6] - Configuring additional features