0x05 (0x05) — Path destination unknown

The path parsed correctly, but the object, instance, or attribute it names does not exist on this device. Compare with 0x04, where parsing itself failed.

Start free EtherNet/IP → canonical

Diagnosis

When you hit this

Reading a tag that does not exist in the controller, or was renamed.
Addressing a program-scoped tag as though it were controller-scoped.
An instance number beyond what the device implements.

Resolution

How to fix it

Confirm tag scope
A program-scoped tag needs the program qualifier in its path. Controller-scoped addressing of it returns 0x05.
List the tags
Most controllers support a tag-list service. Enumerate rather than guessing at names.
Watch for case and spelling
Tag names are matched exactly, and a renamed tag fails this way rather than with a clear error.

Normalization

What Forge does about it

This is a configuration or addressing mistake on the wire, upstream of anything Forge sees. Where Forge helps is the step after you fix it: once the point returns data, its vendor tag name maps to a canonical field automatically, so you do not also have to hand-maintain a name table for every point you just re-addressed.