By default, Tacto sends emails from a Tacto address. You can configure a custom sending domain so that outgoing emails appear from your own brand (for example, [email protected] instead of a tacto.ai address). This improves recognition for recipients and typically improves deliverability.
This article walks you through the full setup.
Before you start
You will need:
A domain you control and can edit DNS records for (or a colleague who can add the records on your behalf).
Administrator rights in Tacto for your organization.
About 10 minutes of active work, plus up to 24–48 hours (worst case) of waiting for DNS to propagate before verification succeeds.
Pick a sending subdomain
We recommend using a dedicated subdomain (for example mail.acme.com or tacto.acme.com) rather than your root domain (acme.com). Reasons:
It does not interfere with your existing corporate email setup.
You can remove it later without touching anything else.
Email reputation for the subdomain is independent of your main domain.
If you are unsure, ask your IT team for an unused subdomain to dedicate to Tacto.
Step-by-step setup
Open Tacto and go to Settings → Workspace → General → Email domain.
Click Set up custom domain.
Enter:
Domain – your chosen sending subdomain (for example
mail.acme.com).Display name – the name recipients will see in the From field (for example
Acme Procurement).Email address – the local part before the
@(for exampleno-replyorprocurement). The full address shown in the preview will be<email address>@<domain>.
Click Add domain. Tacto will show you the DNS records you need to add.
Copy each record from Tacto and add it at your DNS provider. See DNS record & common pitfalls below for further information.
Wait for DNS propagation. This usually takes a few minutes but can take up to 24–48 hours depending on your provider.
Back in Tacto, open DNS records and click Verify DNS records. When all required records show as valid, the domain status changes to Active.
Click Send test email and send a test to a mailbox you control to confirm everything works.
Toggle Send emails from your custom domain on. From now on, Tacto will send your organization's emails from this domain. You can switch the toggle off at any time and Tacto will fall back to its default address.
DNS record & common pitfalls
Tacto generates a small set of DNS records when you register a domain. You add them once at your DNS provider; they are read-only thereafter.
For each record, Tacto shows you exactly what to enter as the Host and the Value. Use the copy buttons next to each field to avoid typos.
Host name doubled up. Some providers automatically append your domain to the host you enter. If Tacto says the host is
s1._domainkey.mail.acme.com, your provider may want onlys1._domainkey.mail(it adds.acme.comfor you). Check your provider's documentation if you are unsure.Trailing dots. Some providers expect a trailing dot (
mail.acme.com.), others reject it. Match your provider's convention.Surrounding quotes on TXT records. A few providers add quotes automatically. If you paste a value that already has quotes, you may end up with double quotes. Remove the inner pair if so.
Truncated values. DKIM values are long. Make sure you copy the full value – cutting off the end will silently break verification.
What to do if verification fails
When you click Verify DNS records and one or more records show as Pending, the most common causes are:
DNS has not propagated yet. Wait 10–15 minutes and try again. If you only just added the records, allow up to 24–48 hours.
Host name was entered incorrectly. Double-check the host value character-for-character against what Tacto shows. Watch for the doubled-up host issue described above.
Value was truncated. Particularly likely for the long DKIM TXT record. Re-copy from Tacto using the copy button and paste it again.
Record exists but with the wrong type. Make sure each record's type (TXT, CNAME, MX) matches what Tacto requested. A TXT entered as a CNAME will not validate.
Existing SPF on a parent domain conflicts. This is rare when you use a dedicated subdomain (recommended), because the subdomain has its own SPF. If you registered your apex domain and already have an SPF record, you may need to merge them – contact your IT team or Tacto support.
After fixing any issue, click Verify DNS records again. The verification status and any error message returned by our email provider are shown in the dialog.
What to do if the test email doesn't arrive
If your test email never arrives:
Check the spam or junk folder.
Check whether your organization's mail filter is rejecting it. Try sending the test to a personal address to rule out an internal filter.
Re-verify the DNS records and confirm the sending domain still shows Active in Tacto. The status does not automatically update unless you click verify.
Turning it off or deleting it
You can turn the Send emails from your custom domain toggle off at any time. When it is off, Tacto sends emails from its default address as if you had never configured a custom domain. Nothing breaks, no email is lost.
The same is true if you delete the domain entirely from Tacto: outgoing emails simply fall back to the Tacto default address. You can register a new custom domain (or re-add the same one) at any time.
This makes the toggle a safe kill switch if you suspect a deliverability problem.
FAQ
Can I use my root domain (e.g. acme.com) instead of a subdomain?
Yes, technically. We strongly recommend a subdomain because it isolates Tacto's email reputation from your main corporate mail and avoids any interference with your existing SPF or DKIM setup.
Can my custom domain receive replies?
The custom domain is for sending only. Replies go to whatever address is set as the reply-to in each Tacto email (typically Tacto support), not to the sending address.
How are the keys stored?
Tacto's email provider generates and stores the DKIM signing keys securely on your behalf. You do not need to manage them manually. Keys can be rotated by removing and re-registering the domain.
Who do I contact if I'm stuck?
Send the exact domain name and any error message Tacto shows you to Tacto support. We can check the status from our side and help you diagnose record-by-record if needed.