> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mailofly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Domain Mismatch

> Resolving 403 Forbidden errors caused by unverified sender domains.

If you receive an HTTP `403 Forbidden` error when sending an email with error code `domain_not_verified`:

```json theme={null}
{
  "statusCode": 403,
  "message": "Domain 'company.org' is not verified in your organization.",
  "name": "validation_error"
}
```

***

## Causes & Resolution

1. **Unverified Sender Address**: The domain specified in the `from` parameter must be added and have status **Verified** in your Mailofly dashboard.
2. **Typo in Domain**: Ensure there are no typos in the `from` field (e.g. `user@acme.co` vs `user@acme.com`).
3. **Multi-Organization Context**: If your account belongs to multiple organizations, verify that the API key you are using belongs to the organization that owns the verified domain.


## Related topics

- [Filtering and troubleshooting](/logs/filtering-and-troubleshooting.md)
- [Verify signatures](/webhooks/verify-signatures.md)
- [Manage Domains](/domains/managing-domains.md)
- [Claim domain](/domains/claim-domain.md)
- [Create Domain](/api/domains/create-domain.md)