The request you have made requires authentication.", "code": 401, "title": "Unauthorized

[amurleopard]

As per the error it is an authentication issue, most likely using the wrong credentials for accessing the information you need.

In this case:

$ curl -i -X GET -H X-Auth-Token:tttssfMsdd..... -H "Content-type: application/json" http://localhost:35357/v3/domains
HTTP/1.1 401 Unauthorized
Date: Wed, 22 Set 2016 10:53:54 GMT
Server: Apache/2.4.18 (Ubuntu)
Vary: X-Auth-Token
x-openstack-request-id: req-fdfa4441-444a-469d-8bf7-fbb2d381b68a
WWW-Authenticate: Keystone uri="http://10.50.200.1/identity"
Content-Length: 114
Content-Type: application/json

{"error": {"message": "The request you have made requires authentication.", "code": 401, "title": "Unauthorized"}}

The authentication token is supplied but make sure is it the right one, in later versions of Openstack, the Identity Service (keystone) has the concept of multiple domains and tokens can be for different scope levels project or domain.

In this instance the error was due to using the token generated for project, after changing to a domain token, it worked.