Why are Google Workspace emails not delivering to Proofpoint?
Matthew Whittaker
Co-founder & CTO, Suped
Published 15 Jul 2025
Updated 18 Aug 2025
8 min read
It can be incredibly frustrating when emails from your Google Workspace account mysteriously disappear into the void, failing to reach recipients protected by Proofpoint. This isn't an uncommon scenario, as both systems are designed with robust security features that can sometimes conflict if not properly configured. When emails aren't bouncing back with specific error messages, it suggests that the mail is being silently dropped, often by the recipient's security gateway.
This usually points to underlying issues with domain configuration, sender reputation, or how Proofpoint is interpreting the incoming mail. It’s a bit like trying to send a letter through multiple checkpoints, each with its own set of rules, and one of them decides to discard it without a trace.
Mail flow and routing misconfigurations
One of the primary culprits behind Google Workspace emails not reaching Proofpoint is often a misconfiguration in mail flow settings. Proofpoint acts as an email gateway, meaning all inbound and outbound emails pass through its filtering systems before reaching their final destination. If your Google Workspace isn't configured to route mail properly through Proofpoint, or if Proofpoint isn't expecting mail directly from Google's IP ranges, issues can arise.
Ensuring the correct MX records are in place is critical. MX records direct incoming mail to Proofpoint's servers first, rather than directly to Google Workspace. Additionally, internal routing rules within Google Workspace need to be set up to send outbound mail through Proofpoint’s smart hosts. Without these steps, Proofpoint might see emails directly from Google Workspace IP addresses as suspicious or not authorized to send on behalf of your domain.
Furthermore, it's vital to configure Google Workspace to properly relay emails through Proofpoint. This often involves specific settings in the Google Admin Console, such as setting up a mail route or ensuring that Perform MX lookup on host is not checked. Improper setup can cause a routing loop or prevent Proofpoint from correctly identifying and processing messages.
Sometimes, the issue may not be with outbound routing from Google Workspace, but with how Proofpoint receives mail. If Proofpoint is not configured to accept mail from Google's IP ranges as trusted senders for your domain, it might drop the mail. This happens even if the initial MX records point correctly to Proofpoint. It's crucial that Proofpoint's configuration aligns with Google Workspace as the designated sending source.
Google Workspace Configuration
MX Records: Ensure your domain's MX records point to Proofpoint, not directly to Google Workspace.
Outbound Route: Configure a smart host in Google Workspace to relay all outbound mail through Proofpoint's servers.
SMTP Bypass: Disable any options that allow mail to bypass Proofpoint filters within Google Workspace, such as Perform MX lookup on host.
Email authentication failures (SPF, DKIM, DMARC)
Even with correct mail flow, a common reason for email delivery issues to Proofpoint is a failure in email authentication. This primarily involves SPF, DKIM, and DMARC. Proofpoint relies heavily on these protocols to verify the legitimacy of incoming emails. If these records are misconfigured or fail validation, Proofpoint is likely to block (or blacklist) the email, often without a bounce message back to the sender.
For example, SPF (Sender Policy Framework) issues can occur if Proofpoint's IP addresses are not correctly included in your domain's SPF record, or if Google Workspace is sending mail directly without proper routing through Proofpoint, causing an SPF mismatch. DKIM (DomainKeys Identified Mail) failures might happen if the DKIM signature is invalid or altered during transit. We have a detailed guide on why DKIM might be failing on Gmail, which can be relevant here.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) builds upon SPF and DKIM. A strict DMARC policy (p=reject or p=quarantine) combined with authentication failures can lead Proofpoint to reject emails. This is especially true if you are using multiple domains as aliases on the same Google Workspace account, as a lack of SPF alignment for alias domains on Google Workspace is a frequent pain point.
Regularly checking your authentication records and DMARC reports is crucial. These reports can provide insights into why Proofpoint (or any other receiver) might be blocking (or blacklisting) your emails due to authentication failures. This proactive approach helps identify and fix issues before they significantly impact your deliverability.
Proofpoint, like other email security gateways, employs sophisticated content filtering and sender reputation analysis. Even if your technical configurations are perfect, a poor sender reputation for your domain or the content of your emails can trigger Proofpoint’s filters, leading to silent drops or blocklisting.
Proofpoint is known for its aggressive 'bot click' checks and spam detection, which can sometimes flag legitimate emails. If your organization engages in any form of bulk sending, marketing, or even internal communications that resemble spam, it could negatively impact your domain's reputation in the eyes of Proofpoint. This is particularly relevant if the same return path (bounce address) is used for both corporate mail and any cold outreach, leading to a degraded overall sender reputation.
Content that contains suspicious links, frequently used spam phrases, or attachments known to carry malware can also trigger Proofpoint’s filters. They will hit every link in every email, trying to check if the email is spam. It's essential to audit your email content for anything that might be perceived as malicious or unsolicited. Maintaining a clean sending list and avoiding practices associated with spam are fundamental for good deliverability.
Lastly, being on a public or private email blacklist (or blocklist) can immediately halt email delivery. While you might check major public blocklists, Proofpoint also maintains its own proprietary internal blocklists based on its threat intelligence. If your IP or domain ends up on one of these, even temporarily, your emails will not reach their intended recipients.
Positive reputation factors
Consistent sending: Maintain a regular sending volume without sudden spikes.
Engaged recipients: Encourage opens, clicks, and replies to demonstrate positive engagement.
Low complaint rates: Avoid recipients marking your emails as spam.
Negative reputation factors
High bounce rates: Indicates sending to invalid or non-existent addresses.
When facing email delivery issues to Proofpoint, the first step is always diagnosis. Since you're not receiving bounce messages, the problem likely lies in a configuration that causes silent rejection. This can be tricky, but a systematic approach helps. Checking Proofpoint's logs for specific rejection reasons, even if no bounce is generated, is often the most insightful step. Their logs might show a reason code or policy violation.
Next, review your Google Workspace email routing rules and ensure they align with Proofpoint's requirements. Confirm that your domain's SPF, DKIM, and DMARC records are correctly published and passing validation. Use a free email deliverability tester to check if your email is facing issues even before it hits Proofpoint.
Finally, if you've exhausted all internal troubleshooting, reaching out to Proofpoint support is the logical next step. They can provide specific reasons for why your emails are being dropped, as they have access to granular logging and policy information that isn't publicly available.
Remember, email deliverability is a complex interplay of configurations, reputation, and content. A systematic approach to troubleshooting is always the most effective path to resolution.
Issue
Possible cause
Solution
No bounce message
Silent drop by Proofpoint due to policy or reputation
Check Proofpoint logs and engage their support
Google IPs blocked
Improper Workspace mail routing, or Proofpoint not configured
Verify MX records, smart host settings
Authentication failures
Incorrect SPF, DKIM, or DMARC records, especially with alias domains
Using the same domain for corporate mail and cold outreach, hurting reputation.
Expert tips
Consider engaging a deliverability expert for complex Proofpoint integrations.
Implement consistent sending practices to build positive sender reputation.
Regularly test your email setup with a deliverability checker.
Marketer view
Marketer from Email Geeks says they had a prospective client using Google Workspace that was having issues delivering to Proofpoint, with Google's IPs showing up as blocked.
2025-02-27 - Email Geeks
Marketer view
Marketer from Email Geeks says they suspected domain or content related issues when Google Workspace emails weren't reaching Proofpoint.
2025-02-27 - Email Geeks
Key takeaways
Email deliverability from Google Workspace to Proofpoint requires meticulous configuration and ongoing monitoring. Most issues stem from incorrect mail flow setup, unauthenticated emails due to misconfigured SPF, DKIM, or DMARC records, or a tarnished sender reputation. By systematically checking your DNS records, mail routes, and Proofpoint logs, you can identify and rectify the root causes of non-delivery. Proactive management of your domain's health and adherence to email best practices are key to ensuring your important communications reach their intended recipients without falling into the digital void.
Google Workspace account mysteriously disappear into the void, failing to reach recipients protected by 
Proofpoint. This isn't an uncommon scenario, as both systems are designed with robust security features that can sometimes conflict if not properly configured. When emails aren't bouncing back with specific error messages, it suggests that the mail is being silently dropped, often by the recipient's security gateway.
Google's IP ranges as trusted senders for your domain, it might drop the mail. This happens even if the initial MX records point correctly to Proofpoint. It's crucial that Proofpoint's configuration aligns with Google Workspace as the designated sending source.
