Email at Scale - Removing External Warning Banners from Emails

Recipients of Email at Scale campaigns may see a warning banner at the top of their emails. This article explains why those banners appear and how your IT team can remove them.

Note: This is a recipient-side security control managed by your IT team. ContactMonkey cannot modify or suppress these banners directly.

Why the Warning Banner Appears

Your organization's email security system — such as Microsoft 365, Microsoft Defender for Office 365, Mimecast, or Proofpoint — adds it automatically when an incoming message is classified as coming from outside your organization.

Email at Scale sends campaigns through a dedicated IP address on your senders' behalf. Because that IP address is external infrastructure (not your internal mail server), your security rules flag it as an outside sender and prepend the warning. This is expected behavior from your mail security tooling, not a ContactMonkey bug or deliverability issue.

Prerequisites

• Access to your organization's mail security admin console (Microsoft 365 Exchange Admin Center, Mimecast Administration Console, or equivalent)
• Your ContactMonkey dedicated Email at Scale IP address (provided during feature implementation — contact support@contactmonkey.com if you need to locate it)

How to Remove the Banner

Add an exception to the rule that appends the external warning banner, so that emails from your ContactMonkey dedicated Email at Scale IP are excluded. The steps vary by platform.

Microsoft 365 / Exchange Online

1. Go to Exchange Admin Center → Mail flow → Rules
2. Open the rule that prepends the external warning banner
3. Under Except if, add a condition: The sender IP address is in any of these ranges → enter your dedicated SendGrid IP address
4. Save the rule

Mimecast

1. Log in to the Mimecast Administration Console
2. Navigate to the policy or rule responsible for external sender tagging
3. Add an exception for your ContactMonkey dedicated IP address
4. Save the policy

Proofpoint or Other Gateways

1. Open your gateway's administration console
2. Locate the external sender tagging policy
3. Add an IP-based exception for your ContactMonkey dedicated IP address
4. Refer to your gateway's documentation for platform-specific steps

Still Seeing the Banner?

If the banner persists after adding the IP exception, your security tool may be evaluating other criteria beyond IP address. Complete these checks:

• Verify DNS records — Confirm your SPF, DKIM, and DMARC records are correctly configured for your Email at Scale domain.
• Check your allow list — Ensure ContactMonkey's trusted URLs are added to your organization's Group Policy allow list. See Configuring ContactMonkey's Trusted URLs in Group Policy.