diff --git a/stan.go b/stan.go
index b15a4cc..be052b7 100644
--- a/stan.go
+++ b/stan.go
@@ -176,6 +176,9 @@ func (n *stanBroker) Publish(topic string, msg *broker.Message, opts ...broker.P
 }
 
 func (n *stanBroker) Subscribe(topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	if n.conn == nil {
+		return nil, errors.New("not connected")
+	}
 	var successAutoAck bool
 
 	opt := broker.SubscribeOptions{
@@ -197,7 +200,7 @@ func (n *stanBroker) Subscribe(topic string, handler broker.Handler, opts ...bro
 	}
 
 	var stanOpts []stan.SubscriptionOption
-	if opt.AutoAck {
+	if !opt.AutoAck {
 		stanOpts = append(stanOpts, stan.SetManualAckMode())
 	}
 
@@ -217,6 +220,8 @@ func (n *stanBroker) Subscribe(topic string, handler broker.Handler, opts ...bro
 		}
 	}
 
+	opt.AutoAck = !bopts.ManualAcks
+
 	fn := func(msg *stan.Msg) {
 		var m broker.Message
 		var err error
@@ -224,7 +229,9 @@ func (n *stanBroker) Subscribe(topic string, handler broker.Handler, opts ...bro
 			return
 		}
 		err = handler(&publication{m: &m, msg: msg, t: msg.Subject})
-		if err == nil && successAutoAck && bopts.ManualAcks {
+		if err == nil && successAutoAck && !opt.AutoAck {
+			msg.Ack()
+		} else if err != nil && opt.AutoAck {
 			msg.Ack()
 		}
 	}