diff --git a/server/src/ngsi.c b/server/src/ngsi.c
index 06eb187c1..a08293c43 100644
--- a/server/src/ngsi.c
+++ b/server/src/ngsi.c
@@ -1,3 +1,4 @@
+
 /** Node type: OMA Next Generation Services Interface 10 (NGSI) (FIWARE context broker)
  *
  * This file implements the NGSI context interface. NGSI is RESTful HTTP is specified by
@@ -326,10 +327,13 @@ int ngsi_read(struct node *n, struct msg *pool, int poolsize, int first, int cnt
 int ngsi_write(struct node *n, struct msg *pool, int poolsize, int first, int cnt)
 {
 	struct ngsi *i = n->ngsi;
-	struct msg *m = &pool[first];
-	
+	struct msg *m = &pool[first % poolsize];
+
+	if (cnt > 1)
+		error("NGSI nodes only can send a single message at once");
+
 	/* Update context */
-	for (int j = 0; j < i->context_len; j++) {
+	for (int j = 0; j < MIN(i->context_len, m->length); j++) {
 		json_t *attribute = i->context_map[j];
 		json_t *value = json_object_get(attribute, "value");
 		json_t *metadatas = json_object_get(attribute, "metadatas");
@@ -366,4 +370,4 @@ int ngsi_write(struct node *n, struct msg *pool, int poolsize, int first, int cn
 	return 1;
 }
 
-REGISTER_NODE_TYPE(NGSI, "ngsi", ngsi)
\ No newline at end of file
+REGISTER_NODE_TYPE(NGSI, "ngsi", ngsi)