When using the 'attach' icon to attach files, the green loading bars appear for a while, then they stop but nothing is attached. When using the drag-and-drop method to attach, an alert is displayed stating "You do not have ability to attach file to this record"
The issue is intermittent.
This may be caused by a slow executing WRITE ACL custom script on the table where attachment is being attempted (not the sys_attachment table).
Customers can re-write the custom ACL script to make it more efficient.