小弟最近在使用 python + mongodb + celery 時遇到 RuntimeError 這個問題，想上來問問前輩們有沒有遇過類似的問題或可能的情況

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/celery/app/trace.py", line 451, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/celery/app/trace.py", line 734, in __protected_call__
    return self.run(*args, **kwargs)
  File "/celery_app/tasks.py", line 352, in period_search_tasks
    break
  File "/usr/local/lib/python3.8/contextlib.py", line 131, in __exit__
    self.gen.throw(type, value, traceback)
  File "/core/utils/mongodb_utils.py", line 14, in get_db
    db_client.close()
  File "/usr/local/lib/python3.8/site-packages/pymongo/mongo_client.py", line 1342, in close
    self._end_sessions(session_ids)
  File "/usr/local/lib/python3.8/site-packages/pymongo/mongo_client.py", line 1310, in _end_sessions
    with self._socket_for_reads(ReadPreference.PRIMARY_PREFERRED, None) as (
  File "/usr/local/lib/python3.8/contextlib.py", line 113, in __enter__
    return next(self.gen)
  File "/usr/local/lib/python3.8/site-packages/pymongo/mongo_client.py", line 1476, in _socket_for_reads
    topology = self._get_topology()
  File "/usr/local/lib/python3.8/site-packages/pymongo/mongo_client.py", line 1385, in _get_topology
    self._kill_cursors_executor.open()
  File "/usr/local/lib/python3.8/site-packages/pymongo/periodic_executor.py", line 86, in open
    thread.start()
  File "/usr/local/lib/python3.8/threading.py", line 852, in start
    _start_new_thread(self._bootstrap, ())
RuntimeError: can't start new thread