Hi! How can I reset my Outlook/Exchange postmaster messages? I think there is one unsend messages somewhere, replaying few address " couldnt be delivery" and this messages will be sent several times /hour to my post. How can I stop this automatic "loop"???? I cant see any messages my send-box, ist really empty. But some or someone? will be sent the same messages again and again...

you can check in queue viewer using Exchange Toolbox.

You can also run get-queue or get-message to check if its on the list.

Good article here : https://technet.microsoft.com/en-us/library/bb123535%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396