Summary
When your Brand Indicators for Message Identification (BIMI) logo isn't appearing on a specific marketing subdomain, despite working on other subdomains or your main domain, it often points to a nuanced DMARC configuration issue. While the primary domain might have a robust DMARC policy, subdomains can sometimes require their own explicit DMARC records to ensure BIMI displays correctly.
Key findings
- DMARC policy necessity: For BIMI to display, the sending domain or subdomain must pass DMARC validation with a policy of p=quarantine or p=reject. A p=none policy will not enable BIMI display.
- Subdomain DMARC inheritance: Even if your organizational domain has a DMARC record with a restrictive sp= (subdomain policy) tag, some mailbox providers may still require an explicit DMARC record for the specific subdomain where BIMI is intended to appear.
- Consistent configuration: The marketing subdomain must meet all BIMI requirements independently, including proper DMARC alignment, SPF, and DKIM, even if the parent domain is fully compliant. Ensure your DMARC, SPF, and DKIM records are correctly set up for the specific subdomain.
- Reputation impacts: While not directly a BIMI requirement, a subdomain's reputation can indirectly affect whether email clients display supplementary features like BIMI. Low reputation might lead to logos not showing, even if technically configured correctly. Regularly monitor your domain reputation.
Key considerations
- Explicit DMARC for subdomain: If your marketing subdomain is not displaying BIMI, adding an explicit DMARC record (e.g., v=DMARC1; p=reject;) directly on that subdomain is a primary troubleshooting step. This overrides any inherited policy.
- VMC placement: Ensure your Verified Mark Certificate (VMC) covers the specific subdomain you are trying to enable BIMI on, even if it's issued for the main domain.
- Sender alignment: Verify that the 'From' header, DKIM 'd=' tag, and SPF 'Return-Path' (Envelope From) align with the marketing subdomain. Misalignment can lead to DMARC failure.
- DNS propagation time: After making any DNS changes, allow sufficient time for records to propagate globally. This can sometimes take up to 48 hours.
- Testing tools: Utilize online BIMI checkers and DMARC validators to ensure your records are correctly published and interpreted by different mail servers. The BIMI Group provides resources to help, such as their BIMI FAQ for senders.
What email marketers say
Email marketers often face challenges with BIMI implementation on subdomains, even when the primary domain is working flawlessly. Their experiences highlight the nuances of DMARC policies and how different email clients interpret them, particularly regarding subdomain inheritance and the need for explicit configurations. The consensus leans towards ensuring each sending subdomain has a robust, passing DMARC policy.
Key opinions
- Subdomain policies: Many marketers find that explicitly setting a DMARC policy on the subdomain, rather than relying solely on the main domain's sp= tag, is often the solution to getting BIMI to display consistently.
- DMARC enforcement: The requirement for DMARC to pass at an enforced policy (quarantine or reject) is universally acknowledged as the fundamental prerequisite for BIMI to work on any domain or subdomain.
- Volume and reputation: While not a direct cause of BIMI failure, maintaining consistent sending volume and a strong domain reputation on the marketing subdomain is seen as crucial for overall deliverability and the successful display of auxiliary features.
- Client-specific behavior: Marketers frequently note that BIMI display can vary across email clients like Gmail, Yahoo, and AOL, even with identical configurations, suggesting slight differences in their interpretation or implementation of the standard. For example, some find their BIMI logo isn't showing in Gmail but appears elsewhere.
Key considerations
- Subdomain DMARC scope: Consider if the marketing subdomain should inherit the parent domain's DMARC policy or have its own. Explicit policies on subdomains often provide more control and predictability for BIMI.
- Troubleshooting methodology: When BIMI is not showing, a systematic approach is needed, checking all authentication records (SPF, DKIM, DMARC) for the specific sending subdomain, not just the organizational domain. A useful starting point can be found in this guide on BIMI implementation.
- Avoiding conflicts: Ensure that any DMARC record on the marketing subdomain does not conflict with or inadvertently weaken the DMARC policy of the main domain or other subdomains. Proper BIMI implementation for subdomains is key.
- Monitoring and testing: Continuous monitoring of DMARC reports and testing BIMI display across various email clients after any changes are vital for confirming successful implementation.
Marketer view
An email marketer from Email Geeks suggests ensuring the marketing subdomain doesn't have its own conflicting DMARC policy. This means if the main domain has an sp=reject policy, an explicit p=none on the subdomain could prevent BIMI from showing. Sometimes, a specific subdomain DMARC can override the organizational one.
Marketer view
A marketer from Mailup.com explains that the first step to activating the BIMI standard is to verify that a restrictive DMARC policy (quarantine or reject) is enabled for the domain in question on the main domain. Without this, BIMI will not function. This policy ensures proper email authentication is in place.
What the experts say
Email deliverability experts agree that DMARC enforcement is the cornerstone of BIMI functionality. While an organizational domain's DMARC record with a subdomain policy (`sp=`) *should* apply to all subdomains, practical experience shows that sometimes an explicit DMARC record on a subdomain is still required for BIMI to display reliably. They stress the importance of thorough diagnostics beyond just top-level domain settings.
Key opinions
- DMARC enforcement is paramount: Experts consistently point to the DMARC policy (specifically p=quarantine or p=reject) as the primary trigger for BIMI display, regardless of the domain level.
- Explicit subdomain DMARC: Despite DMARC's design for parent domain policies to cover subdomains via sp=, experts often find that adding an explicit DMARC record directly to the subdomain (even if redundant in theory) resolves BIMI display issues. This suggests variations in how different mailbox providers process DMARC inheritance.
- Hidden factors: Problems with BIMI not showing can stem from factors beyond visible DNS records, such as domain reputation, which might differ between subdomains even within the same organizational domain. For more insights, refer to our guide on hidden factors affecting deliverability.
- Diagnostic approach: General troubleshooting of BIMI issues requires a detailed look at the specific subdomain's setup, rather than assuming it inherits all properties from the main domain. Tools that check all technical details can be invaluable.
Key considerations
- Subdomain DMARC policy choice: If you are setting an explicit DMARC record on a subdomain, ensure the policy (p=) is set to quarantine or reject to satisfy BIMI requirements. A p=none policy will not trigger BIMI display.
- Consistency across subdomains: While transactional subdomains might have different DMARC needs (e.g., p=quarantine), marketing subdomains typically benefit from stronger DMARC enforcement for BIMI. Ensure consistency where appropriate or understand the implications of divergence.
- Thorough testing: After implementing or modifying DMARC on a subdomain, send test emails to various mailbox providers (Gmail, Yahoo, AOL, etc.) to confirm BIMI display. Tools like our troubleshooter for BIMI logo issues can help.
- Monitor DMARC reports: Regularly review DMARC aggregate reports to ensure that emails sent from the marketing subdomain are passing authentication checks as expected. This data provides insights into any potential issues hindering BIMI. For more, see our guide to DMARC reports.
Expert view
An expert from Email Geeks states that enforcing DMARC to pass is the main thing required for BIMI. This fundamental requirement ensures that the sending domain is properly authenticated, which is a prerequisite for email clients to consider displaying the BIMI logo. Without DMARC enforcement, BIMI will not work.
Expert view
An expert from Word to the Wise explains that DMARC is generally designed to go on the parent or organizational domain. This means that a single DMARC record, when correctly configured with an sp= tag, should theoretically cover all subdomains. However, real-world implementation can sometimes differ.
What the documentation says
BIMI documentation consistently highlights DMARC as a prerequisite for logo display. While DMARC policies are designed to cascade from organizational domains to subdomains via the sp= tag, it also acknowledges scenarios where explicit subdomain DMARC records might be beneficial or even necessary for consistent enforcement and BIMI functionality across all email clients.
Key findings
- DMARC prerequisite: The BIMI Group's documentation explicitly states that BIMI depends on passing DMARC with an enforced policy (quarantine or reject). A DMARC record with p=none will not enable BIMI.
- Subdomain inheritance: According to the BIMI Group, the protocol allows for subdomains to inherit the BIMI record from the organizational domain if a specific subdomain record is not published. However, this inheritance is contingent on the DMARC policy's sp= tag.
- VMC and logo requirements: BIMI display also requires a valid SVG logo hosted over HTTPS and often a Verified Mark Certificate (VMC) issued by an accredited certificate authority. Ensure your VMC explicitly covers the domain or subdomain in question.
- Mailbox provider discretion: Even with all technical requirements met, the final decision to display a BIMI logo rests with the individual mailbox provider, which may consider factors beyond mere authentication, like sender reputation.
Key considerations
- DMARC policy for subdomains: Review the DMARC sp= tag on your organizational domain's DMARC record. If it's set to sp=none, each subdomain requires its own DMARC record to enable BIMI. If it's sp=quarantine or sp=reject, subdomains should inherit, but explicit records can still resolve issues.
- BIMI record location: Publish the BIMI TXT record directly for the specific marketing subdomain, for example, default._bimi.marketing.example.com, to ensure it is explicitly available. This overrides any potential inheritance issues.
- SVG and VMC validation: Ensure your SVG logo is properly formatted and publicly accessible over HTTPS. If using a VMC, confirm it is issued for the correct domain/subdomain and the certificate chain is valid. Our guide on validating your BIMI SVG and certificate can assist.
- Selector usage: While not common, BIMI records can use selectors for multiple logos or variations, similar to DKIM. If you are using a selector, ensure it's correctly referenced in your BIMI record for the subdomain. More information on selectors is available from the BIMI Group's introduction to selectors.
Technical article
The BIMI Group FAQs state that if a BIMI record is found at a subdomain, the mailbox provider can use it, even if it differs from the BIMI record published at the organizational domain. This confirms that specific subdomain BIMI records can exist and be prioritized, overriding the parent domain's inheritance.
Technical article
DEV Community's guide to BIMI implementation emphasizes that BIMI depends on passing DMARC. Specifically, it notes that email headers from major providers like Gmail, Microsoft, Yahoo!, or AOL are sure to show DMARC passing if configured correctly. The DMARC policy must be enforced for BIMI to activate.
Related resources
5 resources
Related pages
How to implement BIMI on a subdomain
Does parent domain need BIMI for subdomain to work?
How do I implement DMARC with BIMI on multiple subdomains?
How to set up BIMI records for multiple subdomains
How to apply BIMI to a specific subdomain
A simple guide to DMARC, SPF, and DKIM
DMARC record and policy examples
How to safely transition your DMARC policy
How to troubleshoot BIMI logo not showing after implementation?
Why is my BIMI logo not showing in Gmail and other email clients?
