diff --git a/cmd/gmq-cli/command_conn.go b/cmd/gmq-cli/command_conn.go
index <HASH>..<HASH> 100644
--- a/cmd/gmq-cli/command_conn.go
+++ b/cmd/gmq-cli/command_conn.go
@@ -135,7 +135,7 @@ func newCommandConn(args []string, ctx *context) (*commandConn, error) {
 	host := flg.String("h", defaultHost, "host name of the Server to connect to")
 	port := flg.Uint("p", defaultPort, "port number of the Server to connect to")
 	connackTimeout := flg.Uint(
-		"act",
+		"ackt",
 		defaultCONNACKTimeout,
 		"Timeout in seconds for the Client to wait receiving the CONNACK Packet after sending the CONNECT Packet",
 	)
diff --git a/cmd/gmq-cli/main.go b/cmd/gmq-cli/main.go
index <HASH>..<HASH> 100644
--- a/cmd/gmq-cli/main.go
+++ b/cmd/gmq-cli/main.go
@@ -38,6 +38,15 @@ func main() {
 	// Create a context.
 	ctx := newContext()
 
+	// Launch a goroutine which handles an error.
+	go func() {
+		for err := range ctx.errc {
+			os.Stderr.WriteString("\n")
+			printError(err)
+			printHeader()
+		}
+	}()
+
 	// Create a scanner which reads lines from standard input.
 	scanner := bufio.NewScanner(stdin)
Update cmd/gmq-cli/command_conn.go