Could not delete email attachments in File Manager

As title.

I am using ERPnext cloud.

I just import & sync email, it also import lots of attachments.
However, I couldn’t delete those attachments in File Manager, it shows “No permission to write / remove.”
I saw someone face same problem :

I am pretty sure I got every permission I could.
Not only in Setting user role to select all possible roles, but also added permission in “User Permissions Manager”
But non of those work.

Could somebody guide me?

I think it related to this question : Bug when deleting emails with file attachments

Because of file sizes, now, these undelete-able attachments stopping me do anything, even create a sales invoice…

To delete the File you will need to give the Role Delete permission first, Please go the Role Permission Manager, select the File as doctype and then select the Role and check the delete property.

Thanks, @makarand_b

and I actually done that, but still not working. this is my current setting.