Error on /usr/bin/aker/aker.py

[mg1boc1]

when i trying to start aker i got this error:

$ /usr/bin/aker/aker.py Traceback (most recent call last): File "/usr/bin/aker/aker.py", line 180, in Aker().build_tui() File "/usr/bin/aker/aker.py", line 130, in init self.user = User(self.posix_user) File "/usr/bin/aker/aker.py", line 81, in init self.hosts = Hosts(config, self.name, gateway_hostgroup, idp) File "/usr/bin/aker/hosts.py", line 88, in init self.idp = IdPFactory.getIdP(idp)(config, username, gateway_hostgroup) File "/usr/bin/aker/idp/IPA.py", line 33, in init api.Backend.rpcclient.connect() File "/usr/lib/python2.7/site-packages/ipalib/backend.py", line 69, in connect conn = self.create_connection(*args, **kw) File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 1067, in create_connection command([], {}) File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 1281, in _call return self.request(name, args) File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 1248, in request verbose=self.__verbose >= 3, File "/usr/lib64/python2.7/xmlrpclib.py", line 1273, in request return self.single_request(host, handler, request_body, verbose) File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 699, in single_request self.get_auth_info() File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 651, in get_auth_info self._handle_exception(e, service=service) File "/usr/lib/python2.7/site-packages/ipalib/rpc.py", line 610, in _handle_exception raise errors.KerberosError(message=unicode(e)) ipalib.errors.KerberosError: Major (851968): Unspecified GSS failure. Minor code may provide more information, Minor (39756044): Credential cache is empty