Bench Error: "Fault 10: 'BAD_NAME'

buntu@ip-172-31-47-101:~/frappe-bench$ bench restart
INFO:bench.utils:sudo supervisorctl restart frappe:
error: <class 'xmlrpclib.Fault'>, <Fault 10: 'BAD_NAME: frappe'>: file: /usr/lib/python2.7/xmlrpclib.py line: 794
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 11, in <module>
    load_entry_point('bench', 'console_scripts', 'bench')()
  File "/home/ubuntu/.bench/bench/cli.py", line 40, in cli
    bench_command()
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 716, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1060, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/home/ubuntu/.bench/bench/commands/utils.py", line 19, in restart
    restart_supervisor_processes(bench_path='.', web_workers=web)
  File "/home/ubuntu/.bench/bench/utils.py", line 387, in restart_supervisor_processes
    exec_cmd('sudo supervisorctl restart {group}'.format(group=group), cwd=bench_path)
  File "/home/ubuntu/.bench/bench/utils.py", line 140, in exec_cmd
    raise CommandFailedError(cmd)
bench.utils.CommandFailedError: sudo supervisorctl restart frappe: