Isso parece o mesmo problema postado aqui: link
talvez o servidor de autenticação tenha um problema temporal.
detalhes do status.log:
2014-02-20 20:56:57,621 - ubuntuone.status - DEBUG - server connection lost
2014-02-20 20:58:57,695 - ubuntuone.status - DEBUG - server connection made
2014-02-20 20:58:58,118 - ubuntuone.status - DEBUG - server connection lost
...
detalhes de syncdaemon.log:
2014-02-20 21:00:58,126 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection started to host fs-1.one.ubuntu.com, port 443.
2014-02-20 21:00:58,168 - ubuntuone.SyncDaemon.ActionQueue - INFO - Connection made.
2014-02-20 21:00:58,169 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection made.
2014-02-20 21:00:58,412 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'protocol_version' finished OK.
2014-02-20 21:00:58,690 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'caps_raising_if_not_accepted' finished OK.
2014-02-20 21:00:58,931 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'caps_raising_if_not_accepted' finished OK.
2014-02-20 21:00:59,138 - ubuntuone.SyncDaemon.ActionQueue - INFO - The request 'oauth_authenticate' failed with the error: TRY_AGAIN and was handled with the event: SYS_SERVER_ERROR
2014-02-20 21:00:59,139 - ubuntuone.SyncDaemon.StorageClient - INFO - Connection lost, reason: [Failure instance: Traceback (failure with no frames): <class 'twisted.internet.error.ConnectionLost'>: Connection to the other side was lost in a non-clean fashion: Connection lost.
].
2014-02-20 21:00:59,140 - ubuntuone.SyncDaemon.ActionQueue - WARNING - Connection lost: Connection was closed cleanly.
detalhes de credentials.log:
2014-02-20 21:08:42,870 - ubuntuone.credentials - DEBUG - login: args (<ubuntuone.platform.credentials.CredentialsManagementTool object at 0xaaf734c>,), kwargs {'window_id': 0}.
2014-02-20 21:08:43,213 - ubuntuone.credentials - INFO - Starting Ubuntu One login manager for bus 'com.ubuntuone.Credentials'.
2014-02-20 21:08:43,217 - ubuntuone.credentials - DEBUG - ref_count is 0, changing value to 1.
2014-02-20 21:08:43,522 - ubuntuone.credentials - DEBUG - Handling DBus signal for member: 'CredentialsFound', app_name: dbus.String(u'Ubuntu One').
2014-02-20 21:08:43,522 - ubuntuone.credentials - INFO - 'CredentialsFound'
2014-02-20 21:08:43,522 - ubuntuone.credentials - DEBUG - ref_count is 1, changing value to 0.
2014-02-20 21:08:43,522 - ubuntuone.credentials - DEBUG - Setting up timer with <function timeout_add at 0xb6af6c6c> (10000, <bound method CredentialsManagement.shutdown of <ubuntuone.platform.credentials.dbus_service.CredentialsManagement at /credentials at 0x9af08cc>>).
2014-02-20 21:08:43,523 - ubuntuone.credentials - INFO - CredentialsManagement: emitting CredentialsFound.
2014-02-20 21:08:43,524 - ubuntuone.credentials - DEBUG - cleanup: removing signal match <<class 'dbus.connection.SignalMatch'> at a7eaa4c "type='signal',sender='com.ubuntuone.Credentials',path='/credentials',interface='com.ubuntuone.CredentialsManagement',member='CredentialsFound'" on conn <dbus._dbus.SessionBus (session) at 0xa98d4dc>>
2014-02-20 21:08:43,524 - ubuntuone.credentials - DEBUG - cleanup: removing signal match <<class 'dbus.connection.SignalMatch'> at a7ea44c "type='signal',sender='com.ubuntuone.Credentials',path='/credentials',interface='com.ubuntuone.CredentialsManagement',member='AuthorizationDenied'" on conn <dbus._dbus.SessionBus (session) at 0xa98d4dc>>
2014-02-20 21:08:43,524 - ubuntuone.credentials - DEBUG - cleanup: removing signal match <<class 'dbus.connection.SignalMatch'> at a7ea86c "type='signal',sender='com.ubuntuone.Credentials',path='/credentials',interface='com.ubuntuone.CredentialsManagement',member='CredentialsError'" on conn <dbus._dbus.SessionBus (session) at 0xa98d4dc>>
2014-02-20 21:08:53,533 - ubuntuone.credentials - DEBUG - shutdown!, ref_count is 0.
2014-02-20 21:08:53,533 - ubuntuone.credentials - INFO - Shutting down, calling <gi.FunctionInfo object (quit) at 0x0x9af0780>.