A network engineer notices a sudden interruption to the HSRP adjacency between the switches.

The correct remediation is key1 accept-lifetime 00:00:00 Jun 01 2018 23:59:59 Sep 01 2020. In Cisco data center troubleshooting, the first priority is to isolate whether the failure is caused by the underlay, overlay control plane, first-hop gateway behavior, or a consistency parameter. This item is centered on HSRP, so the selected action targets the condition that prevents normal forwarding rather than masking the symptom. Cisco Nexus and ACI guidance treats vPC, VXLAN EVPN, OTV, OSPF, BGP, HSRP, and LACP issues as state-dependent technologies: a neighbor, peer, VLAN, VNI, multicast group, timer, MTU, or policy mismatch can leave the protocol partially operational while traffic is still dropped. The rejected alternatives either change unrelated attributes, introduce a new inconsistency, or affect only a secondary behavior. The operational check after applying the fix should be to confirm adjacency or peer state, validate the relevant route/MAC/endpoint table, and test traffic in the affected VLAN or VRF. This aligns with Cisco DCIT network troubleshooting methodology for isolating control-plane state before changing data-plane policy.