Not able to update user email in resource directory

Summary:

We are Implementing Help Desk application. We need to add a person as Queue resource. We are getting error while we add the person to the queue.When we checked it is because the user was not having email in the resource directory. We followed some methods to update the email still the same issue occur. We require immediate solution for this. This is happeing to only one user.

Oracle SR is also raised already and they have asked us to post the q and only in production.estions in the forum. Please help us out to solve this issue.