Zoho Projects API Scope for Issue Attachments

Zoho Projects API Scope for Issue Attachments

I try to download issue attachments via the API, unfortunately I always get the following error code when trying to download the file from the supplied URL:  {"ERROR_MESSAGE":"INVALID_OAUTHSCOPE","ERROR_CODE":401} 
indicating an auth scope error. I've tried various scope combinations, but so far nothing worked. The url I get from the attachmets looks like follows:
https://download.zoho.eu/webdownload?x-service=projects&event-id=projects-a50cb4cd679062f6d7013bc3a8161959d80df8c2b6d227b585b34108da5fb4a1898c668705052fb88a54e9b6e2ffa228a93b243a4c87d73b1e65624a980f73239a8bace06bdcc296cd30e320645e05371f (replaced a few digits here)
What is the correct oatch scope to add? This "ZohoProjects.portals.READ,ZohoProjects.projects.READ,ZohoProjects.bugs.READ,ZohoProjects.documents.READ,ZohoProjects.attachments.ALL,ZohoProjects.search.READ,WorkDrive.workspace.ALL,WorkDrive.files.ALL,WorkDrive.team.ALL,ZohoPC.files.ALL" doesn't work