Check the below comments
This method can only be called by server administrators or site administrators. In addition, site administrators have some limitations in what changes they can make to users:
- Site administrators cannot set thefullNamevalue.
- Site administrators can change theemailandpasswordvalues only if the caller is a site administrator for all sites that the user is a member of.
- Site administrators can change thesiteRolevalue only if the site is configured to allow site administrators to add and remove site users.
Hope this helps Kindly mark this answer as correct/helpful so that it will help others
I'm the site administrator and thus able to add and remove site users(Tableau Online). It's just the update part which seems to not work.