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

# SSL error ERR_CERT_COMMON_NAME_INVALID

## Cause and Resolution

This error usually indicates one of two things:

* You created a CNAME to an [Endpoint](https://www.aptible.com/docs/core-concepts/apps/connecting-to-apps/app-endpoints/overview.md) configured to use a [Default Domain](https://www.aptible.com/docs/core-concepts/apps/connecting-to-apps/app-endpoints/default-domain.md). That won't work; use a [Custom Domain](https://www.aptible.com/docs/core-concepts/apps/connecting-to-apps/app-endpoints/custom-domain.md) instead.

* The [Custom Certificate](https://www.aptible.com/docs/core-concepts/apps/connecting-to-apps/app-endpoints/custom-certificate.md) you provided for your Endpoint is not valid for the [Custom Domain](https://www.aptible.com/docs/core-concepts/apps/connecting-to-apps/app-endpoints/custom-domain.md) you're using. Get a valid certificate for the domain.