End User Applications - Configuring POP3 in Microsoft Outlook

This article contains information on configuring a POP account in Microsoft Outlook to connect directly to Mimecast, including prerequisites, setup steps, and bypassing anti-spoofing policies for seamless email sending and receiving.

Overview

Email can be sent and received from any device or application that supports the POP and SMTP protocols. In this guide, we will configure Microsoft Outlook to connect directly to Mimecast to send and receive emails instead of using an email server.

Considerations

POP services are not available for metadata-only accounts. It is important to note the following:

• The IMAP4 protocol is unsupported.
• A five-day rolling window of emails is accessible through the POP connector.
• Mimecast requires that encryption through port 587 be used.
• If the email client has been configured to use encryption, but the encryption negotiation fails, Mimecast will not accept the connection.
• Mobile devices can be configured with the same settings as defined below. For configuration guidelines, consult your mobile phone software documentation.
• The Mimecast Internal Domain user (who is creating a POP account in Microsoft Outlook) must also have the POP and SMTP options enabled before emails can be sent and received using these protocols.
• Although LDAP and cloud passwords are accepted for POP connections, new messages can only be sent outbound via SMTP Authentication when using a Mimecast Cloud password. We recommend that any users accessing these features utilize a cloud password for both services.

Creating a POP account in Microsoft Outlook

You can create a POP account in Microsoft Outlook by using the following steps:

1. Open the Email Account Settings in Outlook:
2. Click on New to launch the New Account wizard.
3. Select the Let Me Set Up My Account Manually option.
4. Click on the Next button.
5. Select the option for Internet E-mail.
6. Click on Next.
7. Complete the information in the following fields:

Field / Option	Description	Example Entry
Your Name	The name of the user that appears in the Headers of sent emails.	John Smith
E-mail Address	The email address for the mailbox.	[e-mail]
Account Type	Defines the protocols to be used for this connection.	POP3
Incoming Mail Server	The server from which emails should be fetched. It is important to enable SSL Encryption and to use port 995, as described later in this article.	Europe (excluding Germany): eu-pop.mimecast.com Germany: de-pop.mimecast.com United States of America: us-pop.mimecast.com United States of America B: usb-pop.mimecast.com Canada: ca-pop.mimecast.com South Africa: za-pop.mimecast.co.za Australia: au-pop.mimecast.com Offshore: je-pop.mimecast.com
Outgoing Mail Server	The server to which emails should be sent. It is important to enable TLSEncryption and to use port 587, as described later in this article.	Europe (excluding Germany): eu-smtp-outbound-1.mimecast.com eu-smtp-outbound-2.mimecast.com Germany: de-smtp-outbound-1.mimecast.com de-smtp-outbound-2.mimecast.com United States of America: us-smtp-outbound-1.mimecast.com us-smtp-outbound-2.mimecast.com United States of America B: usb-smtp-outbound-1.mimecast.com usb-smtp-outbound-2.mimecast.com Canada: ca-smtp-outbound-1.mimecast.com ca-smtp-outbound-2.mimecast.com South Africa: za-smtp-outbound-1.mimecast.co.za za-smtp-outbound-2.mimecast.co.za Australia: au-smtp-outbound-1.mimecast.com au-smtp-outbound-2.mimecast.com Offshore: je-smtp-outbound-1.mimecast-offshore.com je-smtp-outbound-2.mimecast-offshore.com
Username	The user's email address.	[e-mail]
Password	The Mimecast Cloud password.	(Request from your administrator). Although LDAP and Cloud passwords are accepted for POP connections, new messages can only be sent outbound via SMTP Authentication when using a Mimecast Cloud password. Mimecast, therefore, recommends that any users accessing these features utilize a cloud password for both services.

8. Click on the More Settings button.
9. Click on the Outgoing Server tab.
10. Select the My Outgoing Server (SMTP) Requires Authentication option.
11. Select the Use Same Settings as my Incoming Mail Server option.
12. Click on the Advanced tab.
13. Change:
    • The Incoming server (POP3) is from 110 to 995.
    • Select the Server Requires an Encrypted Connection (SSL) option.
    • The Outgoing Server (SMTP) Port 587.
    • Set the Encrypted Connection Type to TLS.
14. Some TLS or SSL connections require a Digital Certificate to be in place on both mail servers (i.e., on the customer server and the Mimecast server).

It is recommended to deselect the option Leave a copy of the message on the server. This will avoid repeatedly downloading all the email contents during the Send/Receive process, if Microsoft Outlook's local cache of recently downloaded messages is missing or corrupt.

15. Click on OK to save the changes.
16. Click on Next in the wizard to test the account.
17. Click on Finish once the test is successful.
18. Click on Close to return to Outlook.

Bypassing the Anti-Spoofing Policy

Anti-Spoofing Policies may be enabled in specific customer accounts to prevent unauthorized access to your Mimecast mail service. This is evident if the test email step 9 in the section above, Creating a POP account in Outlook, results in an error: 550 Anti-Spoofing policy - Inbound not allowed. In this instance, the Administrator must enable a bypass policy for your email address(es) in the Mimecast Administration Console.

Troubleshooting Authentication Issues

If you're experiencing authentication issues with your POP account in Outlook, try the following troubleshooting steps:

1. Verify your login credentials by attempting to log in to the Mimecast Personal Portal.
2. Try logging into Outlook Web App to isolate whether the issue is specific to your local Outlook client.
3. Check that your authentication logs show successful login attempts.
4. Confirm that your credentials are correct and up-to-date.