Email Blocking for Invalid or Restricted Recipient Domains

The platform blocks outbound emails before sending when the recipient email domain is invalid or restricted for security reasons. This prevents sends to domains that can increase security risk or lead to failed delivery — keeping your sender reputation safe.

What Is Restricted Domain Blocking?

Restricted Domain Blocking is a pre-send validation that prevents outbound email when a contact's email domain (the part after @ ) is invalid or restricted. When the block triggers, the platform does not attempt to send the email.

Key Benefits

How It Works

The platform validates the recipient email address domain before attempting to send.

If the domain is invalid or restricted, the platform blocks the send before it leaves.

The contact's email cannot be used for outbound communications until the address is updated to one on a permitted domain.

What You Will See

When an email address is blocked, an inline warning appears under the contact's Email field:

"This email address is invalid as the domain is restricted for security reasons."

How to Resolve

Check for typos — especially in the domain after the @ symbol.

Replace the address with a valid email on a permitted domain. Once updated, outbound sends can resume normally.

If this is a recipient domain you genuinely need to reach, raise a Support ticket and include:

• The recipient domain (example: )
• Where you saw the warning (Contact record, Conversations, Campaigns, Workflows, etc.)
• The sub-account name or ID
• The sending method (Adaptive AI Email, Adaptive AI Email, or custom SMTP)

There is no in-app override for the block. The address must be replaced with a permitted one for sending to resume.

Frequently Asked Questions

Before you begin

“Email Blocking for Invalid or Restricted Recipient Domains” is part of the Marketing → Email Marketing area in Adaptive AI. Build templates, broadcasts, campaigns, and performance reporting. Email configuration affects deliverability, reputation, consent, and reporting. Test the exact sender, content, links, and recipient state before sending to a real audience. The objective is not merely to save a setting; it is to confirm the result works for the staff member or customer who will depend on it.

• Confirm the sending domain or provider is connected, authenticated, and approved for the From address you plan to use.
• Verify the audience has appropriate consent and exclude unsubscribed, bounced, suppressed, or otherwise restricted recipients.
• Prepare a small internal test segment with multiple mailbox providers and complete contact fields for merge-value testing.
• Review the subject, preview text, sender name, reply-to address, links, fallback values, and required business identification.
• Check whether the email is part of a campaign, workflow, course, invoice, or system notification so you test the correct sending path.

Verify the result

After completing the instructions in this guide, use a controlled test before treating the setup as finished. A saved screen or success message confirms configuration, but only an end-to-end test confirms the business outcome.

1. 1Send to the internal test segment and confirm each mailbox receives the message from the intended sender without broken merge values.
2. 2Open the message on desktop and mobile, then test every link, image, button, reply path, and unsubscribe control.
3. 3Review delivery logs for accepted, delivered, bounced, blocked, complained, opened, and clicked events where available.
4. 4Confirm replies return to the correct inbox and that the related contact conversation or workflow updates as intended.
5. 5Only expand the audience after the test content, recipient filters, timing, and tracking behavior are all correct.

Troubleshooting checklist

If the result differs from what you expected, preserve the current state and isolate one variable at a time. Start with the checks below before deleting the configuration or rebuilding it from scratch.

• Check domain authentication, provider status, From-address alignment, and sending limits when messages are rejected or never leave the queue.
• Review suppression, bounce, complaint, unsubscribe, and invalid-domain status for a recipient-specific delivery failure.
• Use the email log and provider response rather than repeated test sends to identify the exact rejection or deferral reason.
• Confirm merge fields have fallback values and that the test contact contains the data expected by the template.
• Compare campaign or workflow scheduling, account time zone, smart-send rules, and quiet hours when delivery is delayed.

Best practices

• Send relevant content to well-defined segments and avoid sudden volume increases that can damage domain reputation.
• Use one recognizable sender identity, working reply path, accurate subject, and clear unsubscribe option in marketing messages.
• Remove chronically invalid addresses and investigate complaint or bounce spikes before sending the next campaign.
• Keep templates focused, accessible, mobile-readable, and free of unnecessary tracking or image weight.
• Record major sender, domain, audience, and automation changes so deliverability shifts can be traced to a specific event.