Whitelisting Your Email Sending Domain
Learn why emails from your Knack app might not be delivered, and how to whitelist your sending domain so emails come from your own domain instead of knack.com.
What You'll Learn
Whitelisting your email sending domain tells Knack's email system that your domain is a verified, legitimate sender. This article covers why emails from your app might not be delivered, how to request whitelisting, and what it does for you.
Why Emails Might Not Be Delivered
If emails from your app aren't reaching inboxes, or show a "dropped" or "bounced" status in your email history, the most common cause is an unwhitelisted sending domain.
Check your email history firstBefore requesting whitelisting, confirm the delivery issue in
Flows > Historyor your app's email history. See Understanding the Email History for how to read delivery statuses.
What Whitelisting Does
By default, emails from your app are sent using a knack.com sending address behind the scenes, even if your app's "from" address is set to your own domain. Whitelisting changes this so emails are actually sent and authenticated from your domain.
This matters for deliverability. Many inbox providers use sender authentication to decide whether to deliver, flag, or reject a message.
How to Request Whitelisting
- Submit the whitelist request form.
- Knack sends back instructions for the DNS entries you'll need to add at your domain provider.
- Add those DNS entries. Propagation can take up to a day before validation completes.
- Once validated, emails sent from your app will come from your domain instead of knack.com.
If you don't hear back or want to check on request status, contact the Knack Support team.
Verify this linkThe whitelist request form link above is carried over from the previous version of this article and should be confirmed as current before publishing. A separate HubSpot form link used for custom domain requests was confirmed live during this update, but it's a different form for a different purpose and shouldn't be reused here without checking with the team first.
If Whitelisting Is Already Set Up and Emails Still Aren't Delivered
If support confirms your domain is already validated and emails still aren't arriving, the issue is likely on the receiving end rather than with Knack. This can happen when a recipient's network blocks emails that are sent from and to the same domain.
SPF and DKIM
Knack's whitelisting process doesn't use the terms SPF or DKIM directly, but it accomplishes something similar. Whitelisting is handled through Knack's email provider using CNAME-based domain authentication, which functions the same way DKIM does: it lets receiving mail servers verify that email claiming to be from your domain is actually authorized to send on your behalf.
Once your domain is whitelisted, a 2048-bit key is used for that authentication.
Next Steps
- Understanding the Email History: Read delivery statuses like dropped, bounced, and delivered.
- How Do I White Label My App?: See how domain whitelisting fits into fully white labeling your app.
- Custom Domains for Your Next-Gen Live App: Set up a branded URL for your app.
Updated about 7 hours ago