Find what is different between them and you'll most likely find the cause of the problem.

>"A" and "B" are different users, both with administrator rols.
>
>>Are users "A" and "B" different Windows users or different logins to SMTP server?
>>
>>>Yes, sure. Please check
>>>http://c-dev.net/vfp/mail.txt
>>>
>>>It's the same Craig Boyd's example with my parameters.
>>>Weirdest yet, in the same PC works fine with user "A" and not with user "B".
>>>This is driving me crazy :)
>>>
>>>