Labeled attachments are not showing up on the attachments macro

If you label attachments and use the Attachments Macro to display attachments by label it will not display any attachments.

Steps to Reproduce:

1. Setup a Confluence 5.5.3.
2. Into a test space add a attachment.
3. Give a label to that attachment (test).
4. Now create a test page into the new space.
5. Add the attachments macro add test at the "Attachments labels" field:
   
6. Save.
7. Notice that the attachment added in step 2 will not show up.

Resolution

Upgrade to Confluence 5.6.3.