You want information on the required "User Roles" for a portal user to run Email Delivery Troubleshooting Tool in the ClientNet Portal.
ClientNet > Dashboard > [Tools] > Email Delivery Troubleshooting Tool
Access to run the tool should be restricted to those users with the Permission either the Edit Configurations on Mail Platform for All Domains or Track and Trace, as it is those users who will have the correct kind of access to fix many of the issues diagnosed.
If the user has full access then the user has this access by default. Otherwise, access can be added by selecting the Service user role and then selecting one or more of the services that you wish the user to access.
To assign permissions for an individual user account:
This role must be assigned by the Primary/administrive login.
This will give the portal user access to run the tool by default.