If you set the "Email" attribute on the details of a user in OneClick in the Users tab; that email address will be used for the "From" address when that user sends email from OneClick.
Unable to email alarms from OneClick
Error Message: May 23, 2007 12:58:17 PM - Error emailing troubleshooter at email@example.com:
501 Syntax Error In Parameters Or Arguments.
Microsoft Windows 2000
Microsoft Windows 2003
Causes of this problem:
SMTP server required value in 'From' field in order to send emails from OneClick and the OneClick user did not have the email address parameter populated
Some SMTP servers demand that certain parameters such as the 'From' email address are supplied or else the email is rejected. Setting up the just SMTP parameters in the OneClick admin page does not let the user specify a 'From' field.
(Legacy KB ID CNC TS24511 )