Why are Google Workspace emails not delivering to Proofpoint?

Key findings

• Domain reputation: The primary cause of non-delivery to Proofpoint is often tied to the sending domain's reputation, not necessarily an IP blocklist, indicating a deeper trust issue.
• No bounce message: If emails are not delivering but no bounce message is received, it suggests a silent block by Proofpoint, which is a common response to perceived spam or malicious content.
• SPF alignment for alias domains: Google Workspace setups with multiple alias domains frequently encounter SPF alignment issues, as shared return paths can complicate authentication and impact deliverability.
• Impact of cold outreach: Using a corporate domain for cold email outreach (sales or marketing) can quickly degrade its reputation, leading to blocks by security gateways like Proofpoint.

Key considerations

• Review authentication records: Ensure your SPF, DKIM, and DMARC records are correctly configured and aligned, especially when using alias domains within Google Workspace. This is a critical step in preventing unauthenticated sender errors.
• Monitor sender reputation: Regularly check your domain's sender reputation to identify potential issues before they impact deliverability. A poor reputation (possibly due to unsolicited mail) will lead to blocks from services like Proofpoint.
• Dedicated IP vs. domain: Understand that a dedicated IP address does not automatically solve underlying domain reputation problems. Focus on improving domain health first.
• Proofpoint configuration: Verify that Proofpoint is correctly configured to accept mail from your Google Workspace environment.

Key opinions

• Domain over IP: Marketers generally agree that domain reputation, rather than specific IP blacklists, is the more likely cause for Proofpoint rejections.
• Silent blocking: The absence of a rejection message is a strong indicator of a silent block, which means the email is simply dropped without notification.
• Alias domain complexities: Managing multiple alias domains under one Google Workspace account can create significant challenges for email authentication and deliverability.
• Cold outreach impact: If a domain is used for cold outreach, it significantly increases the risk of being blocklisted or silently rejected by mail security solutions like Proofpoint.

Key considerations

• Diagnose silent blocks: When no bounce is received, investigate potential issues with Proofpoint's logging or filtering to understand why messages are being dropped.
• Separate sending practices: Avoid mixing transactional or corporate emails with bulk or cold outreach campaigns on the same domain or Google Workspace account to preserve sender reputation.
• Content analysis: Analyze email content for spam triggers. Proofpoint's advanced filters might be flagging specific words, phrases, or embedded elements.
• Engage recipient support: When issues persist, contacting the recipient's IT team or Proofpoint administrator can provide specific insights into their filtering policies.

Key opinions

• SPF alignment critical: Lack of SPF alignment for alias domains in Google Workspace is a common problem impacting deliverability.
• Beyond cold leads: These SPF issues can occur even when the domain is not engaged in cold outreach, indicating a fundamental configuration challenge.
• Microsoft's strictness: While Proofpoint's specific policy on SPF alignment blocks is less observed by some experts, Microsoft is known to block based on these issues.
• Underlying authentication: Proper email authentication (SPF, DKIM, DMARC) is foundational for ensuring emails pass through sophisticated filters like Proofpoint's.

Key considerations

• Verify SPF records for aliases: Carefully check and correct SPF alignment for all alias domains configured in Google Workspace to prevent delivery failures.
• Implement DMARC: A robust DMARC policy, especially in quarantine or reject mode, can signal to receivers like Proofpoint that your domain is legitimate and reduce the likelihood of blocks due to authentication failures. Consider also fixing common DMARC issues.
• Consult Proofpoint support: If issues persist, engaging directly with Proofpoint support is crucial to understand their specific filtering logic for your emails and domain.
• Address unauthenticated errors: Fix any 550 5.7.26 unauthenticated sender errors by correctly implementing SPF and DKIM.

Key findings

• Mail gateway configuration: Google Workspace must be specifically configured to use Proofpoint Essentials as its mail gateway to ensure all outbound and inbound mail passes through it.
• MX lookup settings: Documentation often advises against performing MX lookup on the host within Google Workspace settings when integrating with Proofpoint, ensuring correct routing.
• Authentication protocols: Crucial authentication protocols are required for Google Workspace emails to pass through security filters, aligning with new industry standards from major mailbox providers.
• Phishing and malware detection: Proofpoint actively blocks emails that it detects as phishing attempts or containing malware, regardless of the sending platform.

Key considerations

• Follow configuration guides: Adhere strictly to the official setup documentation provided by Proofpoint and Google Workspace for seamless integration.
• Prioritize authentication setup: Ensure SPF, DKIM, and DMARC are properly implemented and aligned. This is fundamental for avoiding unauthenticated sender errors.
• Content best practices: Maintain clean email content to avoid triggering Proofpoint's phishing and malware detection filters.
• Monitor internal bounces: Be aware that Google itself can block its own IP addresses in certain internal mail routing scenarios, which can cause bounce errors.