Handle KNOT_MSG_UNREGISTER_REQ message on STATE_AUTHENTICATING state.
diff --git a/src/knot_thing_protocol.c b/src/knot_thing_protocol.c
index 2ac7942..859be03 100644
--- a/src/knot_thing_protocol.c
+++ b/src/knot_thing_protocol.c
@@ -299,6 +299,14 @@
 	if (nbytes <= 0)
 		return nbytes;
 
+	if (msg.hdr.type == KNOT_MSG_UNREGISTER_REQ) {
+		handle_unregister();
+		return -1;
+	}
+
+	if (msg.hdr.type != KNOT_MSG_AUTH_RESP)
+		return -1;
+
 	if (msg.action.result != KNOT_SUCCESS)
 		return -1;
 	return 0;