[Mimedefang] multiplexor dies after killing slave

[Ingo]

Hello,

it is not the first time, this happens to my mailserver:

after this message in the maillog:
[date] xxx mimedefang-multiplexor[12263]: Killing idle slave 0 (pid 12264): Slave has processed 500 requests

these messages occure:
[date] xxx mimedefang[12278]: MXCommand: connect: Connection refused: Is multiplexor running?
[date] xxx mimedefang[12278]: mfconnect: Error communicating with multiplexor

what do you think did I do wrong to the multiplexor and how can I help
it to stay alive?

Bye - Ingo.