The POST /environments/{environmentId}/signOnPolicies operation creates a new sign-on policy resource. In the request body, the name property is required, and the sign-on policy name must be unique within the environment. All other properties are optional.

The default property is set automatically to false. You can’t set default to true when you first create the sign-on policy. You’ll need to use PUT {{apiPath}}/environments/{{envID}}/signOnPolicies/{{policyID}} to set default to true.