Before running SSRS Subscription Manager please ensure you have to correct permissions set.

 

 

 

SSRS Native Permission Requirements

 

 

There are four System Role permissions of interest.

 

 

 

 

 

 

 

 

 Permissions Required for Managing Subscriptions

 

 Note this is a User Role not a System Role.

 

 

 

 

 Edit the user role the user is a member of.  In the screenshot below the role is My Reports but you can create an additional User Role and permission the user to that role.

 Best Practice is to use a domain group  user > group > Role  (User Role and System Role)

 

 

 

 

 

SSRS Integrated Permissions Required

 

 https://docs.microsoft.com/en-us/sql/reporting-services/security/set-permissions-for-report-server-operations-in-a-sharepoint-web-application?view=sql-server-2017#permissionSharedSchedules

 

 

 

 

 

 SSRS Role Tasks vs SharePoint Group Permissions

 

 https://docs.microsoft.com/en-us/sql/reporting-services/security/reporting-services-roles-tasks-vs-sharepoint-groups-permissions?view=sql-server-2017