KB486735: "Privilege type 'xyz' is not a valid privilege type" error occurs when editing a user's privilege in MicroStrategy Workstation.

Symptom
When displaying a user's privilege in Strategy Workstation, the following error appears:
 

PrivilegeType 301 is not valid privilege type

Cause
This error normally occurs when the Intelligence Server and Library Server versions do not match. In this particular instance, privilege type 301 corresponds to "Add KPI to Insights", which is a privilege that was first released in Strategy 2021 Update 7. It is likely that the Library Server is of an older version. 
Action
Make sure the Intelligence Server and Library Server versions match.