Cannot create new at Confluence onDemand using REST API.
Steps to reproduce:

• generate new instance of Confluence onDemand without any additional products;
• using any tool execute REST request:

  Authorization: Basic, with username/password
  URL: https://<instance>.atlassian.net/rest/api/2/user?expand=groups
  Headers: Content-Type=application/json, Accept=application/json
  Body:
  {
  "name":"testuser0002@mail.com",
  "password":"Abcd1234",
  "emailAddress":"testuser0002@mail.com",
  "displayName":"Test User0002",
  "notification":false
  }
  

Expected result:

• new user created

Actual result:

• response with code 503 (Service Temporarily Unavailable)

Affected versions:

• Confluence onDemand 5.9.1-OD-2015.39.1-0001

Workaround:

• add JIRA to existing instance of Confluence