Refer to the exhibit from an HPE Aruba Networking CX6000:Two CX 6000 switches are configured...

LACP (Link Aggregation Control Protocol) modes can be active or passive. When two switches are both configured in passive mode, no LACP packets are initiated, causing the link aggregation to fail or go into a block state.

Changing one side from passive to active causes that switch to initiate LACP negotiation, resolving the block state.

Changing to static mode disables LACP negotiation, which is not recommended unless both sides are static.

Changing timeout does not solve LACP block issues caused by mode mismatches.

Therefore, changing one switch’s LACP mode from passive to active is necessary to resolve the block.