diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index cf416f6e..6663b8e9 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -983,7 +983,7 @@ lwip_netconn_do_delconn(struct api_msg_msg *msg)
   if (((msg->conn->state != NETCONN_NONE) &&
        (msg->conn->state != NETCONN_LISTEN) &&
        (msg->conn->state != NETCONN_CONNECT)) ||
-      (msg->conn->state == NETCONN_CONNECT) && !IN_NONBLOCKING_CONNECT(msg->conn)) {
+      ((msg->conn->state == NETCONN_CONNECT) && !IN_NONBLOCKING_CONNECT(msg->conn))) {
     /* This means either a blocking write or blocking connect is running
        (nonblocking write returns and sets state to NONE) */
     msg->err = ERR_INPROGRESS;