I have a filter setup, that has everything enabled, except "Delivered", so I can see if something didn't get returned, or if there was a delivery error.
I came across USPS delivery error, that says "Unknown - No Access", and it wasn't displaying on my list, because I think that specific is not listed in the filter.
This is what I have selected, everything except "Delivered" and the error above, does not show up on the list.