Hi all, in my network (client) application I have to defer an action in a thread using deferToThread. I add an errBack to the deferred returned from the deferToThread in order to handle exceptions and, then, I add a callBack in order to return a response *anyway*. Now the problem: if the thread completes its execution without exception, everything works pretty fine. If an exception happens in the thread, then the errBack is invoked, the callBack is invoked and the transport.write is invoked but... at the end of the chain the protocol receives a "connectionLost" call and the factory receives a "clientConnectionLost" call, both with the reason you can see in the subject. What does it mean? Any help would be greatly appreciated. Python 2.3.3 Twisted 1.2.0 Best regards Matteo