You are troubleshooting a complex routing issue after a recent change.

When a recent routing change causes an outage affecting all users, the recommended immediate action is to restore the last-known working configuration to quickly return the network to a stable state. This is critical to minimize downtime and impact.

Asking customers to send logs or explaining the issue takes time and delays remediation.

Collecting show tech and opening TAC cases can be done after restoring service.

Hence, the quickest way to mitigate the impact is to restore the last known good configuration.