twisted.python.failure.Failure twisted.internet.error.ConnectionDone: Connection was closed cleanly.

This error message indicates that a connection to a network resource was closed in a clean and expected manner. The "twisted.python.failure.Failure" part of the message refers to the Python module used to handle errors and exceptions in the Twisted networking framework. The "twisted.internet.error.ConnectionDone" part specifically refers to the fact that the connection was closed cleanly, without any errors or unexpected behavior. This can happen, for example, when a client completes a request and the server sends a response indicating that the connection should be closed.