The issue is related to missing permissions, You need to grant the following permissions to the user profile:
- View Event Log Files
- API Enabled
- View All Data
To grant these permissions, please follow these steps:
1. Go to Setup and search for Permission Sets.
2. Click New to create a new permission set.
3. Enter a Label and API Name, then click Save.
4. Click on System Permissions.
5. Click the Edit button, then search for and check the boxes for View Event Log Files, API Enabled, and View All Data. Click Save.
6. Click Manage Assignments, then Add Assignment.
7. Select the user profile, click Assign, and then click Done.
Once these permissions are assigned, the error will be resolved, and you will be able to access the Mass File Download tab.