After you configure an access switch on your network, you receive a call that the users have lost connectivity. You examine the trunk interface with the command show interfaces Gi 0/1. What might be the problem?

BPDU Guard was turned on the trunk link. When the BPDU of the adjacent switch was seen, the switch turned the port into err-disable mode. A Spanning Tree loop will not err-disable an interface; it will simply block the offending port. A switch uplink cable that is bad will not place the interface into an err-disable state. Flow control will not have any effect in placing an interface into an err-disable state.