rally verify configure-verifier error

Rally version: 1.5.0

Installed Plugins:
 rally-openstack: 1.4.0

tempest 20.0.0

When I execute rally verify configure-verifier, will report the following error. Can someone help me?

(rally) [yw@localhost ~]$ rally verify configure-verifier
2019-05-16 11:32:50.723 35809 INFO rally.api [-] Configuring verifier 'test0516' (UUID=38b31c96-7eee-49be-8286-cf7a89a2611e) for deployment 'test0516' (UUID=cdb1242c-6898-4a36-a003-ae5c661fbf4d).
Command failed, please check log for more info
2019-05-16 11:32:50.724 35809 CRITICAL rally [-] Unhandled error: AttributeError: 'NoneType' object has no attribute 'clients'
2019-05-16 11:32:50.724 35809 ERROR rally Traceback (most recent call last):
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/bin/rally", line 10, in <module>
2019-05-16 11:32:50.724 35809 ERROR rally sys.exit(main())
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/cli/main.py", line 42, in main
2019-05-16 11:32:50.724 35809 ERROR rally return cliutils.run(sys.argv, categories)
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/cli/cliutils.py", line 674, in run
2019-05-16 11:32:50.724 35809 ERROR rally ret = fn(*fn_args, **fn_kwargs)
2019-05-16 11:32:50.724 35809 ERROR rally File "<decorator-gen-76>", line 2, in configure_verifier
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/cli/envutils.py", line 68, in default_from_global
2019-05-16 11:32:50.724 35809 ERROR rally return f(*args, **kwargs)
2019-05-16 11:32:50.724 35809 ERROR rally File "<decorator-gen-75>", line 2, in configure_verifier
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/cli/envutils.py", line 68, in default_from_global
2019-05-16 11:32:50.724 35809 ERROR rally return f(*args, **kwargs)
2019-05-16 11:32:50.724 35809 ERROR rally File "<decorator-gen-74>", line 2, in configure_verifier
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/plugins/__init__.py", line 51, in ensure_plugins_are_loaded
2019-05-16 11:32:50.724 35809 ERROR rally return f(*args, **kwargs)
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/cli/commands/verify.py", line 357, in configure_verifier
2019-05-16 11:32:50.724 35809 ERROR rally reconfigure=reconfigure)
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally/api.py", line 860, in configure
2019-05-16 11:32:50.724 35809 ERROR rally raw_config = vm.configure(extra_options=extra_options)
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally_openstack/verification/tempest/manager.py", line 106, in configure
2019-05-16 11:32:50.724 35809 ERROR rally tcm = config.TempestConfigfileManager(self.verifier.deployment)
2019-05-16 11:32:50.724 35809 ERROR rally File "/home/yw/rally/lib/python2.7/site-packages/rally_openstack/verification/tempest/config.py", line 37, in __init__
2019-05-16 11:32:50.724 35809 ERROR rally self.clients = self.credential.clients()
2019-05-16 11:32:50.724 35809 ERROR rally AttributeError: 'NoneType' object has no attribute 'clients'
2019-05-16 11:32:50.724 35809 ERROR rally