How to fix a bad Gmail email reputation for a subdomain, and is the Bulk Sender Contact Form effective?
Matthew Whittaker
Co-founder & CTO, Suped
Published 28 May 2025
Updated 19 Aug 2025
7 min read
Dealing with a bad Gmail email reputation for a subdomain can be incredibly frustrating. I've heard countless stories, and experienced some myself, of senders feeling like they're hitting a wall, especially when their emails consistently land in the spam folder despite their best efforts.
Many turn to the Gmail Bulk Sender Contact Form as a last resort, hoping for a direct line to Google's (Gmail's) deliverability team. While it seems like a logical step, its effectiveness is often misunderstood.
In this guide, I'll break down the common reasons a subdomain's Gmail reputation might tank and outline actionable steps you can take to fix it. We'll also address the burning question of whether the Bulk Sender Contact Form is a viable solution.
Understanding subdomain reputation with Gmail
When your email reputation suffers, it's often more than just a single issue. A subdomain's reputation is closely tied to its email sending practices, but also, surprisingly, to the web reputation of the parent domain. Google has indicated that web search reputation can influence email reputation, which is an important consideration for senders.
The purpose of using a subdomain for email sending is to isolate its reputation from your main domain. This strategy means that if your marketing emails, sent from marketing.example.com, encounter deliverability issues, your transactional emails from transactional.example.com remain unaffected. However, this isolation isn't always perfect, and a severely degraded subdomain reputation can sometimes bleed into the main domain.
Monitoring your subdomain's reputation is crucial. Google Postmaster Tools provides valuable insights into your domain's reputation, spam rate, feedback loop data, and authentication status with Gmail. Regularly checking this tool can help you identify issues early. You can learn more about how to improve your domain reputation with Gmail by leveraging these tools.
Essential technical configurations
Before anything else, ensure your technical setup is flawless. Authentication protocols are foundational to email deliverability. Gmail (and other mailbox providers) heavily rely on SPF, DKIM, and DMARC to verify senders and prevent spoofing. If these are incorrectly configured, your emails will likely be flagged as suspicious, regardless of your content or list quality. You can use our free DMARC record generator tool to help get started.
Beyond authentication, also check your reverse DNS records (PTR records) and ensure your server uses a modern TLS/SSL version for encryption. Obsolete encryption can cause delivery issues with major providers like Gmail. These technical elements signal to recipients that your emails are legitimate and safe.
Recommended configurations
SPF (Sender Policy Framework): Ensure your SPF record lists all authorized sending IPs for your subdomain. Misconfigured SPF can lead to rejections or spam folder placement.
DKIM (DomainKeys Identified Mail): Implement DKIM signing for all outgoing emails. A DKIM key of 1024 bits or higher is recommended for stronger security.
DMARC (Domain-based Message Authentication, Reporting & Conformance): Set up a DMARC policy (even a p=none policy initially) to gain visibility into your email authentication status and identify unauthorized senders. You can then gradually move to a more restrictive policy like quarantine or reject.
PTR Records: Ensure your sending IP addresses have valid reverse DNS records that point back to your domain. This provides an additional layer of verification for mailbox providers.
TLS Encryption: Verify that your email server supports and enforces the latest TLS versions for secure communication with recipients. Obsolete TLS versions can cause delivery failures.
User engagement and list hygiene strategies
Once your technical ducks are in a row, the focus shifts to what and to whom you're sending. Mailbox providers, especially Gmail, prioritize user engagement signals. High open rates, click-through rates, and emails being moved from spam to inbox improve your reputation, while low engagement, unsubscribes, and spam complaints hurt it. This is a critical factor in recovering Gmail email deliverability.
Review your list acquisition methods. If you're using single opt-in without any additional validation, you might be collecting unengaged addresses or even spam traps, which can severely damage your sender reputation. A double opt-in process is highly recommended to ensure genuine interest and prevent spam traps.
Segment your audience and send only to your most engaged subscribers, especially during a reputation recovery period. If your emails are going to bulk or spam, stop mailing that segment and focus on those who are actively opening and clicking your messages. This strategy can slowly help rebuild your Gmail sender reputation. Also, ensure your emails include a clear and functional unsubscribe link that is promptly honored.
Bad practices
Purchased lists: Sending to purchased, scraped, or third-party lists, as these often contain spam traps and unengaged users, leading to high complaint rates.
Lack of validation: Not validating email addresses at the point of signup, which can lead to collecting invalid or bot-generated addresses.
Irrelevant content: Sending emails with content that doesn't align with subscriber expectations, resulting in low engagement and high unsubscribe rates.
Infrequent sending: Sending emails too infrequently, causing subscribers to forget they opted in and leading to higher spam complaints.
Good practices
Permission-based lists: Building lists organically through clear opt-in processes like double opt-in to ensure genuine interest.
Engagement segmentation: Segmenting your list based on engagement (e.g., clicks in the last 30-90 days) and prioritizing active subscribers.
Content relevance: Delivering valuable, relevant content that subscribers anticipate and interact with.
Consistent cadence: Maintaining a consistent sending schedule to keep your brand top-of-mind without overwhelming subscribers.
Is the Gmail bulk sender contact form effective?
The Gmail Bulk Sender Contact Form is a tool often used by senders experiencing severe deliverability issues, particularly those with a persistently bad Gmail Postmaster reputation. It allows senders to submit details about their sending practices and email headers to Google for review. However, it's important to manage expectations regarding its effectiveness.
In most cases, you will not receive a direct response from Google after submitting the form. The form's primary purpose is for Google to gather information and, if they identify a technical error on their side or a clear, solvable issue you've overlooked, they might adjust their filters. It is not a customer support channel for individualized troubleshooting or negotiation.
Submitting the form repeatedly without addressing underlying issues will not yield different results. It's crucial to exhaust all other troubleshooting steps, including reviewing your authentication, content, list hygiene, and engagement metrics, before resorting to the form. Think of it as a signal to Google that you're actively trying to resolve issues, but don't rely on it for a magic fix.
Views from the trenches
Marketer from Email Geeks says: I've submitted the Gmail Bulk Sender Contact Form multiple times but haven't received any direct responses or noticeable changes to my subdomain's bad reputation, despite perfect authentication.
Expert from Email Geeks says: Gmail will likely not respond to contact form submissions, but they do adjust their filters internally if they detect a technical error after review.
Expert from Email Geeks says: If your emails are consistently going to the bulk folder, you must stop sending mail to those recipients immediately, as every such delivery negatively impacts your sender reputation.
Marketer from Email Geeks says: Even with 100% SPF, DKIM, and DMARC success rates shown in Google Postmaster Tools, my test accounts land in spam, despite manual efforts to mark them as 'not spam' and engage with the content.
Expert from Email Geeks says: Google recently acknowledged that web search reputation influences email reputation, so any negative activity on your main domain's website could potentially harm your email deliverability.
Best practices
Focus on high user engagement metrics like opens and clicks, as these are crucial signals for Gmail.
Segment your mailing list to only include highly engaged subscribers when trying to improve reputation.
Ensure proper email authentication (SPF, DKIM, DMARC) is in place and verified by Google Postmaster Tools.
Use a 1024-bit DKIM key or higher for stronger cryptographic signatures.
Common pitfalls
Expecting a direct response or immediate fix from the Gmail Bulk Sender Contact Form.
Continuing to send emails to recipients who consistently mark them as spam or have low engagement.
Failing to validate email addresses at signup, which can lead to collecting spam traps.
Ignoring the potential impact of your primary domain's web reputation on your subdomain's email deliverability.
Expert tips
If mail is consistently going to the bulk folder, stop sending to those segments immediately to prevent further reputational damage.
Use open data to identify and prioritize mailing only to recipients who are currently receiving your emails in their inbox.
Consider removing social links or other non-essential elements from your email content if deliverability issues persist.
Regularly monitor your email server's error logs to identify any specific rejection messages or technical issues from Gmail.
Marketer view
Marketer from Email Geeks says: It has been a challenge for at least six months to resolve a bad reputation with Gmail for a subdomain, and three submissions of the Bulk Sender Contact Form have not helped.
2023-08-29 - Email Geeks
Expert view
Expert from Email Geeks says: The 'thanks for submitting' page of the Bulk Sender Contact Form clearly states not to expect a response, but filters may be modified if an error is identified.
2023-08-29 - Email Geeks
Path to recovery: long-term strategies
Fixing a bad Gmail email reputation for a subdomain is a multi-faceted challenge that requires a combination of technical diligence and audience-centric strategies. While the Bulk Sender Contact Form exists, it should be seen as a last resort, not a primary solution, and certainly not a shortcut. The real work lies in ensuring robust authentication, impeccable list hygiene, and consistent engagement from your subscribers. It's a continuous process that demands patience and proactive management.
