Hello,
You may have already tried all of this but since you did not list all your steps I am going to cover what I see is missing from your post.
You must be directly connected to the array for this procedure to work. You cannot do this through a telenet session.
The commands are RESTOREUSERS - you need to add the "S" at the end.
The procedure does work. I have successfully done this in my lab to confirm the process. Since your system is likely still under warranty you can log a Suport case and ask for further assistence.
Cheers,
Shawn
I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.