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

# Error 354

## ERR\_NGROK\_354

Failed to create an endpoint with the domain `DOMAIN`. Nested subdomains of an ngrok base domain `ENDPOINT_DOMAIN` must be reserved first. Alternatively, try `SUGGESTION` instead.

### Possible solutions

* Reserve your subdomain [in the dashboard](https://dashboard.ngrok.com/domains) before starting a tunnel with it.

## Further help

If you're having trouble resolving this error, please reach out to [support@ngrok.com](mailto:support@ngrok.com?subject=Help%20with%20ERR_NGROK_354)