Hi
the error your getting is because your domain group does not have mapping .
error code from Microsoft:
ERROR_SOME_NOT_MAPPED
1301 (0x515)
Some mapping between account names and security IDs was not done.
Can you try the below on Domain Controller:
1. Open "Active directory users and computers" under users--> create new group
2. after create a new group check the properties for the new group and under properties check object tab--> it should list "cononical name of object:"
3. add a user to the group.
Now login in to SnapCenter and create a new role and access the domain name --> click find(it should resolve if machine is joined to the domain properly, you can do nslookup localhost)
and then select the group(if the domain get resolve in Snapcenter Adding new Role wizard it should list groups).