Dear Daniel,
Am Mittwoch, den 15.03.2017, 22:09 +0100 schrieb Daniel Kulesz:
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P.S. Hope this time I've set the Reply-To header correctly.
Note, that you need to set the *In-Reply-To* header field. The field *Reply-To* contains the address used as recipient, when you reply to the message.
Thanks,
Paul