When your Email Recipient's Security Software Blocks Your Emails

Security platform products like Norton and Avast may block bulk emails because their anti-spam and email scanning features can misidentify legitimate mass mailings as spam or a security threat. 

To resolve this, your email recipients can configure the software to allow emails from specific senders or domains, or adjust the email scanning settings. 

Solutions for Norton

• Add Senders to the Allowed List: This is the most effective method for legitimate emails being blocked as spam.
  1. Open your Norton product and click Settings.
  2. In the Settings window, click AntiSpam.
  3. On the Filter tab, next to Allowed List, click Configure.
  4. In the Allowed List window, click Add, enter the email address or domain name, and then click OK.
  5. Click Apply, and then click OK to save changes.
• Disable Outgoing Email Scanning (Advanced Users): If you are sending the bulk emails, you can disable the scanning of outgoing emails. This should be done with caution.
  1. Open your Norton product and click Settings.
  2. Click Antivirus, then the Scans and Risks tab.
  3. Next to Email Antivirus Scan, click Configure.
  4. Uncheck Scan outgoing email messages, click Apply, and select Permanently. 

Solutions for Avast

• Whitelist Email Client in Firewall: Ensure your email client (e.g., Outlook) is allowed through the Avast firewall.
  1. Open Avast and navigate to Protection > Firewall > Apps.
  2. Find your email application (like Microsoft Outlook) and ensure its rules allow internet access (TCP/UDP protocols on relevant ports).
• Disable Email Shield SSL/TLS Scanning: This is often a cause of email connection problems.
  1. Open Avast and go to Menu > Settings.
  2. Navigate to Protection > Core Shields.
  3. Under the Email Shield section, uncheck the box for "Scan inbound and outbound emails (SSL/TLS)".
• Temporarily Disable Antivirus: For troubleshooting purposes, you can temporarily disable Avast shields to confirm the antivirus is the source of the issue.
  1. Right-click the Avast icon in the taskbar.
  2. Select Avast shields control and choose a duration (e.g., Disable for 10 minutes).
  3. Test sending an email. If it goes through, you've confirmed Avast is the issue. Remember to re-enable shields immediately after testing. 

General Advice
As a bulk email sender, ensure your emails follow best practices to avoid being flagged as spam by security software and mailbox providers, please see this article for Tips and Best Practices for Email Marketing