Whenever a particular person in my organization sends a task to another particular person and that receiving person clicks to accept, everything seems normal as they get "Edit the response before sending" or "Send the response now". Now the problem arises when you click (whichever of the 2 options) to send the response, the task does not get accepted and it is not being added to the task list of the receiving person. When you try to click "accept" again the following error comes:

The "<insert task>" cannot be sent. It may be an attachment of another message

It only happens to a specific person receiving tasks from another specific person. I tried using a whole new computer and a fresh "Outlook 2010", but I receive the same error whenever tasks are being sent from that person. Tasks that are sent from other people are received and accepted well. The account of the person who sends the tasks seems to be in order (other people can accept his tasks).

If anyone knows a possible cause or solution to this, I would be more than grateful to that person if such information was shared. Thank you.

Hi,

What type of email account are the two users using?

If it's an IMAP account, please try moving/copying the task to a local pst's Inbox on the recipient's side and then try accepting it from the local pst's Inbox to see the result.

In addition, other community members who had this problem are using IMAP and a few were able to work around the issue by switching to POP3. You may also have a try and let me know the result.

Regards,

Steve Fan
TechNet Community Support