consecutive_connection_failures_before_delay

Each time KumoMTA exhausts the full list of hosts for the destination it increments a consecutive_connection_failures counter. When that counter exceeds the consecutive_connection_failures_before_delay configuration value, KumoMTA will then delay all of the messages currently in the ready queue, generating a transient failure log record with code 451 4.4.1 No answer from any hosts listed in MX.

The default value for this setting is 100.