As you said ,now it works, a new dev/log created each time after i run the code . thank you very much . - Sara

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Subject: Re: twisted.internet.error.CannotListenError: Couldn't listen on any:/dev/log: [Errno 98] Address already in use

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If a unix socket exists, you can't listen on it. Delete /dev/log and you should be able to listen on it again. Jean-Paul