I am facing this trouble above.
I have many other devices connected in this port, all no cisco and no manageable.
I don't have idea what can be,and I have a loop problem in this interface ":%STP-W-LOOPBACKDET: gi1/1/12: STP Loopback Detection.
", I am not sure if is
related.
This switch runs rstp and is the root bridge.
Thanks guys for any help.