First of all, after step 6, you had the newly created cifs server joined the target domain, right?
Secondly, what error or log we got after running the command in step 7?
Anyone from EMC is helping on this or you performed the migration yourself?
Do you Know any similar case?
The error indicates that SID is not able to be query from the source domain. The reason is kind of difficult to tell from here.
I would suggest you either engage EMC Professional Service for this as migration is typical their task or open a service request to support to see whether they are able to help you, which I think you may be told to get EMC field for assistance.