InterfaceError: pool is closing

I am using FastAPI with tortoise orm.
I am trying to handle around 4 to 5 data retrievals and update the data.
Every time I update, I am locking the database row using select_for_update and update the data.
My whole process runs in the background with celery.
I get the below error.
Has anyone faced a similar issue and found a solution to this?

File "/usr/local/lib/python3.10/site-packages/tortoise/queryset.py", line 1006, in _execute
  instance_list = await self._db.executor_class(
File "/usr/local/lib/python3.10/site-packages/tortoise/backends/base/executor.py", line 130, in execute_select
  _, raw_results = await self.db.execute_query(query.get_sql())
File "/usr/local/lib/python3.10/site-packages/tortoise/backends/base_postgres/client.py", line 24, in _translate_exceptions
  return await self._translate_exceptions(func, *args, **kwargs)
File "/usr/local/lib/python3.10/site-packages/tortoise/backends/asyncpg/client.py", line 79, in _translate_exceptions
  return await func(self, *args, **kwargs)
File "/usr/local/lib/python3.10/site-packages/tortoise/backends/asyncpg/client.py", line 126, in execute_query
  async with self.acquire_connection() as connection:
File "/usr/local/lib/python3.10/site-packages/tortoise/backends/base/client.py", line 328, in __aenter__
  self.connection = await self.pool.acquire()
File "/usr/local/lib/python3.10/site-packages/asyncpg/pool.py", line 822, in _acquire
  raise exceptions.InterfaceError('pool is closing')

Start with the traceback locations in tortoise/queryset.py, tortoise/backends/base/executor.py, tortoise/backends/base_postgres/client.py, and tortoise/backends/asyncpg/client.py, then review how the Celery background process initializes and closes the pool. Reproduce the select_for_update and update workflow and identify why acquisition occurs after pool shutdown; done means the workflow completes without InterfaceError.