Recently purchased hub; and I've purchased two smart plugs from list of approved hardware from ZLINK and Interset.
I've followed the manufacturers instructions to the letter on the sequence to press once I put the hub in inclusion mode. However, nothing I get no feed back from the system whatsoever. It doesn't fail and shows nothing in log files other than it started and stopped the inclusion mode. The devices are less than 8 feet away from the hub.
Silly question time but you say you have put the hub in inclusion mode.
Have you put the device in discovery/pairing mode so that it can be discovered by the hub.
I would assume that's accomplished by hitting a button sequence on the device being paired. Both plugs have only 1 button, one brand says hit rapidly 3x times the other is press once.
I've also tried excluding them as well, but again I have no indicator as to if those succeed or not
Before you go too much further check your zwave details page for ghost entries... usually devices with no route information. They can get created during a failed inclusion process and if left unresolved can cause real problems with your mesh.