---
title: "reloop.sh Domain Error"
description: "Why you cannot send from the reloop.sh domain via the public API."
---
> For the complete documentation index, see [llms-docs.txt](/llms-docs.txt) or the site index [llms.txt](/llms.txt). Full docs corpus: [llms-full-docs.txt](/llms-full-docs.txt). Prefer markdown URLs (append `.md`) for agent consumption. Product skill: [skill.md](/skill.md).


Why you cannot send from the `reloop.sh` domain via the public send API.

## Overview

`reloop.sh` (or your deployment's `ONBOARDING_TEST_DOMAIN`) is a **Reloop-owned onboarding test domain**. It is reserved for the onboarding **Send email** button — not for arbitrary customer domain setup.

If you call `POST /api/mail/v1/send` with a From address on that domain, Reloop returns an error directing you to use your own verified domain.

## Common Causes

- Using `onboarding@reloop.sh` (or similar) in a public `/send` request
- Trying to add `reloop.sh` as a customer domain in the dashboard
- Expecting open sandbox sends to any recipient from the platform domain

## What works instead

<Steps>
  <Step title="Onboarding test">
    After generating an API key, click **Send test email to me**. That path sends only to your account email from the platform domain.
  </Step>
  <Step title="Production sending">
    Add your domain in the [dashboard](https://app.reloop.sh/domains), finish DNS verification, then send with a From address on that domain.
  </Step>
  <Step title="Contact support">
    If a legitimate platform test fails, contact [Reloop support](https://reloop.sh/help) with the error payload and approximate time.
  </Step>
</Steps>

## Learn More

- [Email Addresses for Testing](/docs/guides/testing-email-addresses)
- [Domain Not Verifying](/docs/guides/domain-not-verifying)
- [Account Quotas and Limits](/docs/guides/account-quotas-limits)