Custom Domain Configuration Error: "domain: The specified domain name is in an invalid format"
Aug 18, 2025
Okta Classic Engine
Okta Identity Engine
Administration
Overview
Configuring a custom domain under a Brand can sometimes return the following error:
domain: The specified domain name is in an invalid format. Valid format examples are example.com or portal.example.com
Applies To
- Customizations
- Brands
- Custom Domain
Cause
As the displayed error message suggests, there is an issue with the domain format.
Entering, for example, https://portal.example.com would throw this error due to "https:// " which is not required when setting up the domain.
Having a space in front of the new domain (for example, portal.exmple.com) will also throw this error.
Solution
If the domain is named "custom.com" (for example), it must be used like that or a subdomain such as "subdomain.custom.com" (for example), without the need for "https://" or any additional characters, including a space.
