[Limited availability]{class="badge informative"}
Migrate an email subdomain from CNAME to custom delegation migrate-cname-to-custom
If your subdomain is currently set up with CNAMEs, you can migrate it to the Custom delegation method to meet your company’s security policies. This gives you full ownership and control over your subdomains and certificates within Journey Optimizer. Learn more on custom subdomains
As part of this process, you need to:
- Delete the existing DNS records from your hosting solution
- Upload the SSL certificate obtained from the Certificate Authority
- Complete the Feedback Loop steps by verifying domain ownership and reporting email address
- Copy the SSL CDN URL validation record generated by Adobe into your hosting platform
To migrate your subdomain, follow the steps below.
Before you begin before-you-begin
Before you start the migration process, review the important information below.
- Make sure that the Custom delegation method is enabled for your organization (this capability is currently in Limited Availability—contact your Adobe representative to gain access). Learn more
- Ensure that no active channel configurations are using this subdomain. The migration process will interrupt their functionality.
- Ensure that no active campaigns or journeys are using a channel configuration linked to this subdomain as this may cause delivery disruption.
- Be aware that downtime begins as soon as you enter the migration flow. The subdomain moves to Draft during the process and is unavailable until setup is complete.
- Consequently, it is recommended to perform the pre-migration steps before starting the migration process—in order to have your SSL certificate ready and reduce downtime. Learn more
Start the migration start-migration
Follow the steps below to start migrating a given subdomain.
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Go to Administration > Channels > Email settings > Subdomains.
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Select a subdomain set up with CNAMEs and open it.
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You can use the Pre-migration CSR Generation section to generate the CSR for sending it to the Certificate Authority and have the SSL certificate ready when the migration process starts. Learn how
note important IMPORTANT The pre-migration steps are optional at this stage but strongly recommended. Completing them before starting the migration reduces downtime and helps ensure a smooth transition. 
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Select Migrate now in the dedicated section.
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Review the information displayed.
note warning WARNING Downtime begins as soon as you enter the migration flow, so make sure it does not impact your active campaigns and journeys. -
Click Yes. The subdomain moves to Draft status and is unavailable until setup is complete.
Generate and send the CSR to the Certificate Authority send-csr-to-ca
To complete the migration, you need a SSL certificate issued by a Certificate Authority (CA). To receive this SSL certificate, you must first generate a Certificate Signing Request (CSR) and send it to the CA.
Whether you have already started the migration process or not, follow the steps below to generate and send your new CSR.
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Click Regenerate CSR.
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Fill the form that displays and regenerate the Certificate Signing Request (CSR).
note note NOTE The key length can be 2048 or 4096-bit only. It cannot be changed after the subdomain is submitted. -
Click Download CSR and save the form to your local computer.
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Send it to the Certificate Authority (CA) to get your SSL certificate. Before submitting this CSR to your CA for signing, there are a few important points to consider:
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The downloaded CSR from step 3 is only for data.subdomain.com.
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However, the certificate should cover both data.subdomain.com and cdn.subdomain.com as Subject Alternative Names (SAN) entries within a single certificate. For instance, if you are delegating example.adobe.com, then data.subdomain.com corresponds to data.example.adobe.com, and cdn.subdomain.com corresponds to cdn.example.adobe.com.
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Both Data (data.example.adobe.com) and CDN (cdn.example.adobe.com) subdomains need to be added as peer entries in the same certificate.
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Most CAs allow you to add additional SANs (such as the CDN subdomain) during the signing process
- Through the CA portal (recommended, if available), or
- By requesting it manually with their support team if the portal option is not available.
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Once signed, the CA will issue a single certificate covering both the Data domain and the CDN subdomain.
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Delete existing DNS records delete-dns
After starting the migration process, you need to delete the existing DNS records from your hosting solution. Follow the steps below.
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The list of records currently configured in your DNS servers displays.
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Navigate to your domain hosting solution and delete the existing CNAME entries from your DNS hosting.
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Make sure that all the DNS records have been deleted. Once done, check the box “I confirm that I have deleted the required records from hosting site”.
Upload the SSL certificate upload-ssl-certificate
In the SSL Certificate section, you need to upload a new SSL certificate to Journey Optimizer.
Before that, verify the following:
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If you have already sent your CSR to the Certificate Authority as part of the pre-migration steps, make sure you have received your SSL certificate.
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If you haven’t already done so, follow the steps to generate, download and send the CSR.
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One you retrieved your SSL certificate, click Upload certificate.
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Upload the SSL certificate to Journey Optimizer in .pem format with the complete certificate chain. Here is a sample of a .pem file format:
code language-none -----BEGIN CERTIFICATE----- MIIDXTCCAkWgAwIBAgIJALc3... (base64 encoded data) -----END CERTIFICATE----- -
Check the box “I confirm that I have uploaded the SSL certificate”.
Complete feedback loop feedback-loop
Then, complete the feedback loop steps to verify domain ownership and reporting email address.
The process is the same as when setting up a new custom subdomain. Follow the steps detailed on the Set up a custom subdomain page.
Copy the SSL CDN URL validation record copy-ssl-cdn-url-record
To complete the migration process, copy the SSL CDN URL validation record generated by Adobe into your hosting platform. The process is the same as when setting up a new custom subdomain. Follow the steps detailed on the Set up a custom subdomain page.
After submitting, you must wait until Adobe performs the required checks, which can take up to 3 hours. Learn more
Once the subdomain is active again, no changes are needed to existing channel configurations that use it—they continue to work as before.
See also