diff --git a/src/agents/queue/conf.c b/src/agents/queue/conf.c
index f6190ad..2bc0ed6 100644
--- a/src/agents/queue/conf.c
+++ b/src/agents/queue/conf.c
@@ -94,14 +94,14 @@ static BongoConfigItem QueueConfig[] = {
     BONGO_CONFIG_INT("o:queuetuning_load_low/i", &Conf.loadMonitorLow),
     BONGO_CONFIG_INT("o:queuetuning_trigger/i", &Conf.limitTrigger),
     BONGO_CONFIG_INT("o:queuetimeout/i", &Conf.maxLinger),
-    BONGO_CONFIG_INT("o:bounce_queue_timeout/i", &Conf.bounceMaxLinger),
+    BONGO_CONFIG_OPTIONAL_INT("o:bounce_queue_timeout/i", &Conf.bounceMaxLinger),
     { BONGO_JSON_STRING, "o:quotamessage/s", &Conf.quotaMessage },
     BONGO_CONFIG_INT("o:port/i", &Agent.agent.port),
     { BONGO_JSON_BOOL, "o:forwardundeliverable_enabled/b", &Conf.forwardUndeliverableEnabled },
     { BONGO_JSON_STRING, "o:forwardundeliverable_to/s", &Conf.forwardUndeliverableAddress },
     BONGO_CONFIG_INT("o:queueinterval/i", &Conf.queueInterval),
-    BONGO_CONFIG_INT("o:retry_initial_seconds/i", &Conf.retryInitial),
-    BONGO_CONFIG_INT("o:retry_maximum_seconds/i", &Conf.retryMaximum),
+    BONGO_CONFIG_OPTIONAL_INT("o:retry_initial_seconds/i", &Conf.retryInitial),
+    BONGO_CONFIG_OPTIONAL_INT("o:retry_maximum_seconds/i", &Conf.retryMaximum),
     BONGO_CONFIG_INT("o:minimumfreespace/i", &Conf.minimumFree),
     { BONGO_JSON_ARRAY, "o:trustedhosts/a", &trustedHostsConfig },
     { BONGO_JSON_BOOL, "o:rtsantispamconfig_enabled/b", &Conf.bounceBlockSpam },