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This guide walks you through adding the required DNS records for Lettr using Dynadot’s DNS management. Dynadot is a domain registrar that offers DNS hosting for domains registered through its Dynadot account. You will configure a sending domain (CNAME, DKIM TXT, and DMARC TXT records) and, optionally, an inbound domain (MX records), tracking domain (two CNAME records), and storage domain (CNAME and two TXT records).

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Sending Domain Setup

A sending domain authenticates your outgoing emails with DKIM and DMARC, ensuring they are delivered reliably and not marked as spam. This requires a CNAME record for domain verification, a TXT record for DKIM signing, and a TXT record for DMARC policy. To create a sending domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Sending Domains
  3. Click Create Sending Domain
  4. Enter your desired sending subdomain (e.g. mailing.company.com)
  5. Click Create Domain
Use a subdomain (e.g. mailing.company.com) instead of the root domain (company.com). A subdomain provides proper reputation segmentation and is required if you also plan to receive emails with Lettr.
Click your new domain in the Sending Domains list. This will display a list of DNS records that need to be configured. Keep this page open — you will need these values soon.

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Configure Dynadot DNS

Log in to your Dynadot account and navigate to My Domains → Manage Domains. Check the box next to your domain, click the Action button above the domain list, and select DNS Settings from the dropdown. On the DNS settings page, select Dynadot DNS from the top dropdown menu if it is not already selected.
If your domain was registered through Dynadot or your nameservers already point to Dynadot (ns1.dyna-ns.net and ns2.dyna-ns.net), skip nameserver configuration entirely — proceed directly to adding the DNS records below.
If you registered your domain elsewhere but want to manage DNS on Dynadot, you must first update the nameservers at your registrar to Dynadot’s nameservers:
ns1.dyna-ns.net
ns2.dyna-ns.net
Until the nameservers are updated at your registrar, any records you add in Dynadot will not resolve.

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Add CNAME Record

The CNAME record verifies domain ownership with Lettr’s email infrastructure. Copy the CNAME values from Lettr to Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix). For example, paste only mailing.
  3. Set the Record Type dropdown to CNAME.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.
Dynadot automatically appends your domain to the Subdomain field. Always paste only the subdomain portion (e.g. mailing, not mailing.company.com).
Do not add a CNAME record at the root of your domain (e.g. company.com). Like all standard DNS providers, Dynadot does not support CNAME records at the root because they conflict with the NS and SOA records required for DNS to function. Always use a subdomain for your sending, tracking, and storage domains.

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Add TXT Record (DKIM)

The DKIM record adds a cryptographic signature to your outgoing emails, allowing recipients to verify they were sent by an authorized sender. Copy the TXT values from Lettr to Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix). For example, paste only scph0126._domainkey.mailing.
  3. Set the Record Type dropdown to TXT.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.
Dynadot automatically appends your domain to the Subdomain field. Always paste only the subdomain portion (e.g. scph0126._domainkey.mailing, not scph0126._domainkey.mailing.company.com).

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Add TXT Record (DMARC)

The DMARC record tells receiving mail servers how to handle emails that fail authentication checks, protecting your domain from spoofing. Copy the TXT values from Lettr to Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix). For example, paste only _dmarc.mailing.
  3. Set the Record Type dropdown to TXT.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.
Dynadot automatically appends your domain to the Subdomain field. Always paste only the subdomain portion (e.g. _dmarc.mailing, not _dmarc.mailing.company.com).

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Verify Your Sending Domain

After adding all three DNS records, go back to Lettr and click Verify DNS Records. DNS changes on Dynadot propagate in as little as 5 minutes, though it can take up to 48 hours for external resolvers to pick up the changes.

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Inbound Domain Setup

An inbound domain allows Lettr to receive emails on your behalf. This requires three MX records that direct incoming mail to Lettr’s mail servers.

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Add Inbound Domain to Lettr

To create an Inbound domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Inbound Domains
  3. Click Create Inbound Domain
  4. Enter your desired inbound subdomain (e.g. inbound.company.com)
  5. Click Create Domain.
Click on your new domain in the Inbound Domains list. This will display the MX records that need to be configured.

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Add MX Records

MX records tell other mail servers where to deliver emails addressed to your domain. Copy the MX values from Lettr to Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix). For example, paste only inbound.
  3. Set the Record Type dropdown to MX.
  4. Enter rx1.sparkpostmail.com into the IP Address or Target Host field.
  5. Set the Distance field to 10. (Dynadot uses “Distance” instead of “Priority” — they are equivalent.)
  6. Click Save DNS.
  7. Repeat this process for the second (rx2.sparkpostmail.com) and third (rx3.sparkpostmail.com) MX records, each with Distance 10.
Dynadot labels the MX priority field Distance rather than Priority. Set it to 10 for all three records, as Lettr’s MX records are equal-priority. Do not add a trailing period to the MX values — Dynadot handles this automatically.
Adding MX records to a domain or subdomain will route all incoming email for that address to Lettr. Use a dedicated subdomain (e.g. inbound.company.com) to avoid affecting your primary email.

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Verify Your Inbound Domain

After adding all three MX records, go back to Lettr and click Verify DNS Records. DNS changes on Dynadot propagate in as little as 5 minutes, though it can take up to 48 hours for external resolvers.

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Tracking Domain Setup

A tracking domain allows Lettr to track email opens and link clicks using your own custom domain instead of the default Lettr tracking domain. This requires two CNAME records: one for the SSL certificate and one for routing tracking traffic to Lettr’s infrastructure.

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Add Tracking Domain to Lettr

To create a Tracking domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Tracking Domains
  3. Click Create Tracking Domain
  4. Enter your desired tracking subdomain (e.g. tracking.company.com)
  5. Click Create Domain
Click on your new domain in the Tracking Domains list. This will display the CNAME records that need to be configured.

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Add SSL Certificate CNAME Record

The SSL Certificate CNAME record provisions an SSL certificate for your custom tracking domain, enabling secure HTTPS connections for tracked links. Add the record in Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix).
  3. Set the Record Type dropdown to CNAME.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.
Dynadot automatically appends your domain to the Subdomain field. Always paste only the subdomain portion.

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Add Traffic CNAME Record

The Traffic CNAME record routes click and open tracking requests from your custom domain to Lettr’s tracking servers. Add the record in Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix).
  3. Set the Record Type dropdown to CNAME.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.

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Verify Your Tracking Domain

After adding both CNAME records, go back to Lettr and click Verify DNS Records.

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Storage Domain Setup

A storage domain lets you serve email assets (images, attachments) from your own custom domain instead of the default Lettr storage URL. This requires two TXT records for certificate validation and ownership verification, and a CNAME record for routing asset requests to Lettr’s storage infrastructure.

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Add Storage Domain to Lettr

To create a Storage domain in Lettr:
  1. Select Domains in the navigation panel
  2. Select Storage Domains
  3. Click Create Storage Domain
  4. Enter your desired storage subdomain (e.g. assets.company.com)
  5. Click Create Domain
Click on your new domain in the Storage Domains list. This will display the TXT and CNAME records that need to be configured.

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Add TXT Record (Certificate Validation)

The Certificate Validation TXT record provisions an SSL certificate for your custom storage domain, enabling secure HTTPS delivery of email assets. Add the record in Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix).
  3. Set the Record Type dropdown to TXT.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.
Dynadot automatically appends your domain to the Subdomain field. Always paste only the subdomain portion (e.g. assets, not assets.company.com).

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Add TXT Record (Hostname Pre-validation)

The Hostname Pre-validation TXT record verifies ownership of the storage domain before Lettr provisions a custom hostname for it. Add the record in Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix).
  3. Set the Record Type dropdown to TXT.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.

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Add CNAME Record (Domain Routing)

The Domain Routing CNAME record routes asset requests from your custom domain to Lettr’s storage infrastructure. Add the record in Dynadot:
  1. On the DNS Settings page, scroll down to the Subdomain Records (optional) section.
  2. In an empty row, enter the Hostname from Lettr into the Subdomain field (without your domain suffix).
  3. Set the Record Type dropdown to CNAME.
  4. Paste the Value from Lettr into the IP Address or Target Host field.
  5. Click Save DNS.

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Verify Your Storage Domain

After adding all three records, go back to Lettr and click Verify DNS Records.

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Troubleshooting

Dynadot automatically appends your domain to the Subdomain field. If you paste the full hostname (e.g. mailing.company.com), the resulting record will resolve as mailing.company.com.company.com, which will fail verification.Always paste only the subdomain portion:
  • Sending CNAME: mailing
  • DKIM: scph0126._domainkey.mailing
  • DMARC: _dmarc.mailing
  • Inbound: inbound
Dynadot’s default TTL is 300 seconds (5 minutes). Changes typically propagate within minutes on Dynadot’s own nameservers, but external resolvers that have already cached a record will hold their own TTL before refreshing. Propagation can take up to 48 hours globally.If verification fails after adding records, check the following:
  • Wait at least 15–30 minutes before your first verification attempt.
  • Confirm the records exist using command-line tools:
# Check CNAME record
dig CNAME mailing.yourdomain.com +short

# Check DKIM record
dig TXT scph0126._domainkey.mailing.yourdomain.com +short

# Check DMARC record
dig TXT _dmarc.mailing.yourdomain.com +short

# Check MX records (inbound)
dig MX inbound.yourdomain.com +short

# Check tracking domain CNAME
dig CNAME track.yourdomain.com +short

# Check storage domain CNAME
dig CNAME assets.yourdomain.com +short
  • Use a web tool like dnschecker.org to verify propagation across multiple DNS servers worldwide.
If your records are saved in Dynadot but not resolving, confirm that your domain is using Dynadot’s nameservers. You can check this with:
dig NS yourdomain.com +short
The output should include Dynadot’s nameservers:
ns1.dyna-ns.net
ns2.dyna-ns.net
If it shows a different provider’s nameservers, update them at your domain registrar. Nameserver changes can take 4–72 hours to propagate globally.
A common mistake in Dynadot is either selecting the wrong Record Type in the dropdown or entering a record in the Domain Record section (intended for root-level records) instead of the Subdomain Records section.All Lettr records should be entered in the Subdomain Records (optional) section using these types:
RecordCorrect Type
Sending verificationCNAME
DKIMTXT
DMARCTXT
Inbound mailMX
Tracking SSL certificateCNAME
Tracking trafficCNAME
Storage certificate validationTXT
Storage hostname pre-validationTXT
Storage domain routingCNAME
The DKIM TXT value is a long string (256+ characters). After clicking Save DNS, navigate back to the DNS Settings page and confirm the full value is stored in the IP Address or Target Host field. If it appears truncated, delete the record and re-add it, pasting the complete value from Lettr in one operation. Dynadot’s DNS interface does not impose a UI character limit beyond the DNS protocol standard, so paste the value as a single unbroken string.
Dynadot labels the MX priority field Distance instead of the more common term Priority. These are equivalent — set Distance to 10 for all three Lettr MX records. Using equal distance values (10/10/10) allows mail servers to distribute load evenly across all three Lettr inbound servers.
If your DNS records are correctly configured (confirmed with dig or dnschecker.org) and verification still fails after 48 hours, contact Lettr support at support@lettr.com or through the in-app chat. Include your domain name and the output of the dig commands above.

Sending Domains

Learn about sending domain setup, SPF, DKIM, and DMARC.

Inbound Domains

Configure MX records to receive emails with Lettr.

Tracking Domains

Set up a custom tracking domain for click and open tracking.

Storage Domains

Serve email assets from your own custom domain.

Domains Overview

Understand domain types and how they work in Lettr.

Domain Verification Failures

Troubleshoot common DNS configuration and propagation issues.