I am a little confused about assigning the correct roles to users, so here's a question for clarification. Sorry if it's a stupid one.
If you have multiple indexers and search heads, you must assign a user account the necessary role(s) on
b)all search heads,
c)all indexers and search heads
d)none of the above, Splunkers are magicians and can do whatever they want
You need to configure it on you search heads. So option will be (B). On the search heads you need to have the correct roles assigned to proper groups and indexes to have access.