Error raised after about 100 continuous sampling

Hi,

1. Error description

I'm testing a problem necessary to decompose qubits.
So its case should be tested continuously and repeatedly.
By the way, after sampling about 100 continuous sampling,
error was raised as following. Then, whenever a dwave sampler
is instantiated, the error happens.

---------------------------------------------------------------------------
RuntimeError Traceback (most recent call last)
in
1 DWaveSampler(endpoint='https://cloud.dwavesys.com/sapi'
2 , token='DEV-2d82722a40e192fb938da0012c507a9ae3277e31'
----> 3 , solver='DW_2000Q_2_1')

~/anaconda3/envs/tf36/lib/python3.6/site-packages/dwave/system/samplers/dwave_sampler.py in __init__(self, **config)
110 config['solver'] = config.pop('solver_features')
111
--> 112 self.client = Client.from_config(**config)
113 self.solver = self.client.get_solver()
114

~/anaconda3/envs/tf36/lib/python3.6/site-packages/dwave/cloud/client.py in from_config(cls, config_file, profile, client, endpoint, token, solver, proxy, legacy_config_fallback, **kwargs)
316
317 _LOGGER.debug("Final config used for %s.Client(): %r", _client, config)
--> 318 return _clients[_client](**config)
319
320 def __init__(self, endpoint=None, token=None, solver=None, proxy=None,

~/anaconda3/envs/tf36/lib/python3.6/site-packages/dwave/cloud/client.py in __init__(self, endpoint, token, solver, proxy, permissive_ssl, request_timeout, polling_timeout, connection_close, **kwargs)
395 worker = threading.Thread(target=self._do_submit_problems)
396 worker.daemon = True
--> 397 worker.start()
398 self._submission_workers.append(worker)
399

~/anaconda3/envs/tf36/lib/python3.6/threading.py in start(self)
844 _limbo[self] = self
845 try:
--> 846 _start_new_thread(self._bootstrap, ())
847 except Exception:
848 with _active_limbo_lock:

RuntimeError: can't start new thread

2. Expectation.

How to solve this problem?
If there is a limitation of continuous sampling, in a problem necessary to decompose many qubits, how to approach it?

3. Environment.
OS: Mac OS X Sierra 10.12
Python: 3.6

Regards,

Inwoo Chung