LACP bundels several physical network cards together to one logical link. It implements failover if one or more card or link fails and load balancing with different methods.

• https://en.wikipedia.org/wiki/Link_aggregation#Link_Aggregation_Control_Protocol

• https://en.wikipedia.org/wiki/EtherChannel
• https://en.wikipedia.org/wiki/Port_Aggregation_Protocol

If you do not have a connection between a server without active lacp and the switch with active lacp, try

1. add native vlan to allowed vlan list
2. add “no lacp suspend-individual”

  description ExampleSwitchConfiguration
  switchport mode trunk
  switchport trunk native vlan 999
  switchport trunk allowed vlan 999-1100
  spanning-tree port type edge
  no snmp trap link-status
  channel-group 1110 mode active
  no shutdown 
  no lacp suspend-individual