Stacking Problem: stack secure-setup does not see new stack member

[dotan_akiva]

We have an active stack of 5 ICX 6450 switches. I need to add a 6th member. SFP cables are connected correctly but when I issue stack secure-setup, it reports "No new core units found" and just lists the existing 5. 

The new member was removed from a 2-switch stack that we decommissioned.

Before wiring changes, stack looked like this:

    active       standby

-2/1| 1 |2/3--2/1| 2 |2/3--2/1| 3 |2/3--2/1| 4 |2/3--2/1| 5 |2/3-
|-------------------------------------------------------------------------|

I plugged 5/2/3 to 6/2/1 and 6/2/3 back to 1/2/1

Now it looks like this:
    active       standby
     +---+        +---+        +---+        +---+        +---+
  2/1| 1 |2/3--2/1| 2 |2/3--2/1| 3 |2/3--2/1| 4 |2/3--2/1| 5 |2/3
     +---+        +---+        +---+        +---+        +---+

Tried a different switch and also a different SFP cable.

What am I doing wrong?

[BenBeck]

Is the new unit on the exact same code? It should also have a clean (blank) configuration. 

[dotan_akiva]

Thanks, Ben!  Simple enough. I applied same image to the new member and erased config and sure enough, it joined the stack correctly. All set here!