Is you snapdrive user added to the admin group on the filer?
if not please try to check this:
the user should be added to a local group on the filer which is associated with a role having api-* and login-* capabilities.
for this you can do the following. (use useradmin commands on the filer) :
1. create a role on the filer with capabilities api-* and login-*
2. create a group and associate it with the above role
3. add your snapdrive user in this group.
As an alternative you can also directly add the snapdrive user to the default Administrators group on the filer, because this group has all capabilities.