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Use a custom sending domain when you want notification emails to come from your brand — for example, support@yourcompany.com instead of a shared Corsa address. Corsa authenticates your domain with DNS records so recipients see your domain in the From field and mail providers can verify the message.
Only platform owners and platform support users can view or change custom sending domain settings.

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Before you start

You need:
  • Platform owner or platform support access
  • A domain or subdomain you control (for example, mail.yourcompany.com)
  • Access to your DNS provider to add CNAME records
Enable email notifications if you want your team to receive platform notifications by email.

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Register a sending domain

1

Open configuration settings

Go to Settings → Configuration and scroll to Custom Sending Domain.
2

Add a domain

Click Add domain. Enter:
  • Root domain — the domain you authenticate with DNS (for example, mail.yourcompany.com)
  • From email address — the sender address for outbound mail (for example, noreply@mail.yourcompany.com)
The from address must use the same domain you register. If you authenticate mail.yourcompany.com, use an address like noreply@mail.yourcompany.com.Click Create domain.
3

Add DNS records

Click Show DNS on the new domain. Corsa displays the records you must add to your DNS zone:
RecordPurpose
Mail CNAMERoutes outbound mail through the authenticated domain
DKIM 1First DKIM signing key
DKIM 2Second DKIM signing key
Subdomain SPFSPF authorization for the sending subdomain
Each record uses TTL 3600 and class IN. Corsa shows values in BIND-style format:
name TTL IN TYPE rdata
Use the Copy button on each row to copy the full record, or copy the pre-built AWS Route 53 change batch JSON if you manage DNS in Route 53.
DNS changes can take up to 48 hours to propagate. Most providers update within a few minutes to a few hours.
4

Validate the domain

After you add the records, click Validate. Corsa checks each record with the mail provider.
  • Verified — all required records passed validation
  • Pending DNS — one or more records are missing or not yet visible
If validation fails, expand Show DNS to see per-record status and error details, fix the records, and click Validate again.
5

Send a test email

After the domain shows Verified, click Test. Enter a recipient address and send a test message from your configured from address to confirm end-to-end delivery.

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Domain status

StatusMeaning
VerifiedDNS validation passed. Corsa can send mail from the configured from address.
Pending DNSOne or more DNS records are missing, incorrect, or not yet propagated.
DefaultThe first domain you register is marked as default. Additional domains do not replace the default automatically.

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Apply DNS with AWS Route 53

If your DNS is in Route 53, copy the AWS Route 53 change batch JSON from the domain details panel. Save it to a file and apply it with your hosted zone ID: 
aws route53 change-resource-record-sets \
  --hosted-zone-id your-hosted-zone-id \
  --change-batch file://change-batch.json
Replace your-hosted-zone-id with your Route 53 hosted zone ID.

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Manage domains

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Add another domain

Click Add domain to register additional sending domains. Each domain requires its own DNS setup and validation.

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Delete a domain

Click Delete on a domain to remove it from Corsa and the mail provider. Deleting a domain does not remove DNS records from your zone — clean those up manually if you no longer need them.
Deleting a verified domain stops Corsa from sending mail from that from address. Notification emails fall back to the default Corsa sender until you configure and verify another domain.

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Troubleshooting

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Validation shows failed records

Open Show DNS and check the status column for each record. Common causes:
  • The record was added to the wrong DNS zone (root domain instead of subdomain, or vice versa)
  • A typo in the host name or target value
  • DNS has not propagated yet — wait and click Validate again

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From address rejected when creating a domain

The from address must use the exact root domain you register. For domain mail.yourcompany.com, use noreply@mail.yourcompany.com — not @yourcompany.com.

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Domain already in use

Corsa rejects domains that are already registered on your platform or that already have DKIM DNS configured for another mail account. Use a different subdomain or remove conflicting DNS records before retrying.

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Test email not received

Confirm the domain status is Verified, check the recipient spam folder, and verify your DNS records still match the values Corsa displayed.