Python pattern using Bottle Broken Pipe Error framework

I use the Bottle framework that implements the WSGI request and response, and due to a problem with a single thread, I changed the server to PythonWSGIServer and tested it using the Apache scanner, but the result consists of breaking an error that looks like this question How to prevent a damaged errno pipe 32 ? . I tried the answer, but to no avail.

  Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/paste/httpserver.py", line 1068, in process_request_in_thread
    self.finish_request(request, client_address)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 323, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 641, in __init__
    self.finish()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 694, in finish
    self.wfile.flush()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/socket.py", line 303, in flush
    self._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 32] Broken pipe

The server code is below, and I have no idea how to improve the connection using the thread pool?

from paste import httpserver

    @route('/')
    def index():
        connection = pymongo.MongoClient(connectionString)
        db = connection.test
        collection = db.test
        return str(collection.find_one())

    application = default_app()
    httpserver.serve(application, host='127.0.0.1', port=8082)