The Question is:
What could be causing this error
%mail-e-userspec - invalid user specification
The user account works fine on other nodes,
you can send mail to it, etc.
The Answer is :
Check for a logical name that matches the specified username on
the node where the failure occurs.
USERSPEC, invalid user specification 'user-name'
Facility: MAIL, Mail Utility
Explanation: You specified an invalid user name when sending a mail message
to a list of users.
User Action: Ensure that your list contains valid user names and retry the