2.1.e (iv) Etherchannel misconfiguration guard

Etherchannel misconfiguration guard is a feature enabled by default on all switches, if you wish to turn it off (crazy) you may use

no spanning-tree etherchannel guard misconfig
or turn it back on with the
spanning-tree etherchannel guard misconfig

To verify:
show spanning-tree summary


When one side is misconfigured for a static etherchannel the switch will expect to receive the same BPDUs on all ports part of the static etherchannel, if it does not, it puts the ports into errdisable.
Note: STP is required on both ends of the link for this.

The above is the example of it happening. I configured one side for a static etherchannel, and the other side as nothing and turned them up.

The moral of the story of 2.1.e is that you should always use LACP.

best source: