After rebooting my openstack server, when I try to login in the Openstack Dashboard, the login fails and I get this error in the horizon_error.log:

[Sat Sep 14 21:44:31 2013] [error] DEBUG:openstack_auth.backend:Beginning user authentication for user "admin".
[Sat Sep 14 21:44:31 2013] [error] REQ: curl -i -X POST http://127.0.0.1:5000/v2.0/tokens -H "Content-Type: application/json" -H "User-Agent: python-keystoneclient"
[Sat Sep 14 21:44:31 2013] [error] REQ BODY: {"auth": {"passwordCredentials": {"username": "admin", "password": "mysecretpassword"}}}
[Sat Sep 14 21:44:31 2013] [error]
[Sat Sep 14 21:44:31 2013] [error] Starting new HTTP connection (1): 127.0.0.1
[Sat Sep 14 21:44:31 2013] [error] DEBUG:openstack_auth.backend:Authorization Failed: <attribute 'message' of 'exceptions.BaseException' objects> (HTTP Unable to establish connection to http://127.0.0.1:5000/v2.0/tokens)
[Sat Sep 14 21:44:31 2013] [error] WARNING:openstack_auth.forms:Login failed for user "admin".

How can I fix this issue

Best Regards, Pedro