Email domains
By default your follow-up emails are sent from a Custom One address. Connect your own domain and they come from you instead — which is better for recognition, and better for landing in inboxes rather than spam.
It’s set up once for the whole workspace in Workspace settings → Email Domains, and your brands then send from it.
Add the domain
Section titled “Add the domain”Enter the domain you send mail from — example.com. No www, no https://.
You’ll normally use your main domain, the one your business email already uses. A workspace has one sending domain.
Once it’s added you’ll see a table of four DNS records, each with a Status of OK or Not OK. Nothing is sent from your domain until all four read OK.
Add the four records
Section titled “Add the four records”Add these at whoever manages your DNS — your registrar, or a provider like
Cloudflare, OVH or GoDaddy. For example.com they are:
| Name | Type | Value |
|---|---|---|
example.com |
TXT | v=spf1 include:_spf.mailersend.net ~all |
ms1._domainkey.example.com |
CNAME | ms1._domainkey.mailersend.net |
ms2._domainkey.example.com |
CNAME | ms2._domainkey.mailersend.net |
mta.example.com |
CNAME | mailersend.net |
Copy them from the table in Custom One rather than from here — it shows your real domain, already filled in.
All four are required. The two _domainkey records are one signing key split
across two entries: adding only one leaves the domain unverified.
Two mistakes that cost people days
Section titled “Two mistakes that cost people days”Don’t add a second SPF record. If your domain already has a TXT record
starting v=spf1 — most do, if you send any mail at all — edit that one and add
include:_spf.mailersend.net inside it, before the ~all. A domain with two
separate SPF records fails SPF entirely, including for the mail you were already
sending.
Check whether your provider adds your domain for you. Many DNS panels show
your domain beside the name field and append it to whatever you type. There,
enter only the part in front: ms1._domainkey, ms2._domainkey, mta, and @
(or blank) for the SPF record. Pasting the full name into one of those produces
ms1._domainkey.example.com.example.com, which resolves to nothing and looks, in
the table, exactly like having done nothing at all.
Verifying
Section titled “Verifying”Custom One re-checks on its own, and Verify domain checks immediately.
DNS changes are rarely instant. Minutes is common, and providers are allowed to take up to 48 hours. If a record still says Not OK after that, the message under it usually names what was found instead.
A newly added domain is also checked once before it’s registered for sending. If it can’t be approved automatically you’ll be told, and support can look at it.
Using it
Section titled “Using it”Once verified, pick the domain on a brand and that brand’s customs send from it. Brands without one keep sending from the Custom One address.
One address can only do one job: a domain already used to publish your customs can’t also be your sending domain, and Custom One will say so rather than break the one that works.