diff --git a/include/api.h b/include/api.h
index 25cf22a..40c0468 100644
--- a/include/api.h
+++ b/include/api.h
@@ -67,6 +67,6 @@ json_object * api_json_tuples(buffer_t *buf, reading_t *first, reading_t *last);
 /**
  * Parses JSON encoded exception and stores describtion in err
  */
-void api_parse_exception(CURLresponse response, char *err, size_t n);
+int api_parse_exception(CURLresponse response, char *err, size_t n);
 
 #endif /* _API_H_ */
diff --git a/src/api.c b/src/api.c
index d255e3c..2bb536c 100644
--- a/src/api.c
+++ b/src/api.c
@@ -138,31 +138,34 @@ void api_free(api_handle_t *api) {
 	curl_slist_free_all(api->headers);
 }
 
-void api_parse_exception(CURLresponse response, char *err, size_t n) {
+int api_parse_exception(CURLresponse response, char *err, size_t n) {
 	struct json_tokener *json_tok;
 	struct json_object *json_obj;
 
 	json_tok = json_tokener_new();
 	json_obj = json_tokener_parse_ex(json_tok, response.data, response.size);
 
-	if (json_tok->err == json_tokener_success) {
-		json_obj = json_object_object_get(json_obj, "exception");
+	if (json_tok->err != json_tokener_success) {
+		json_tokener_free(json_tok);
+		return ERR;
+	}
 
-		if (json_obj) {
-			snprintf(err, n, "%s: %s",
-				json_object_get_string(json_object_object_get(json_obj,  "type")),
-				json_object_get_string(json_object_object_get(json_obj,  "message"))
-			);
-		}
-		else {
-			strncpy(err, "missing exception", n);
-		}
+	json_obj = json_object_object_get(json_obj, "exception");
+
+	if (json_obj) {
+		snprintf(err, n, "%s: %s",
+			json_object_get_string(json_object_object_get(json_obj,  "type")),
+			json_object_get_string(json_object_object_get(json_obj,  "message"))
+		);
 	}
 	else {
-		strncpy(err, json_tokener_errors[json_tok->err], n);
+		json_object_put(json_obj);
+		json_tokener_free(json_tok);
+		return ERR;
 	}
 
 	json_object_put(json_obj);
 	json_tokener_free(json_tok);
+	return SUCCESS;
 }
 
diff --git a/src/reading.c b/src/reading.c
index a4dcfcb..13765de 100644
--- a/src/reading.c
+++ b/src/reading.c
@@ -36,16 +36,16 @@ char * reading_id_registry(const char *str) {
 	char *found = NULL;
 
 	/* linear search in string list */
-	foreach(strings, it, char *) {
-		if (strcmp(it, str) == 0) {
-			found = it;
+	foreach(strings, it, const char *) {
+		if (strcmp(*it, str) == 0) {
+			found = *it;
 			break;
-			}
+		}
 	}
 
 	if (!found) {
 		found = strdup(str);
-		list_push(strings, found);
+		list_push(&strings, found);
 	}
 
 	return found;
diff --git a/src/threads.c b/src/threads.c
index 63e82ca..eb99beb 100644
--- a/src/threads.c
+++ b/src/threads.c
@@ -199,20 +199,22 @@ void * logging_thread(void *arg) {
 		curl_easy_getinfo(api.curl, CURLINFO_RESPONSE_CODE, &http_code);
 
 		/* check response */
-		if (curl_code == CURLE_OK && http_code == 200) { /* everything is ok */
-			print(log_debug, "Request succeeded with code: %i", ch, http_code);
-			ch->buffer.sent = last->next;
+		if (curl_code != CURLE_OK) {
+			print(log_error, "CURL: %s", ch, curl_easy_strerror(curl_code));
 		}
-		else { /* error */
-			if (curl_code != CURLE_OK) {
-				print(log_error, "CURL: %s", ch, curl_easy_strerror(curl_code));
+		else if (http_code != 200) {
+			char exception[255];
+			if (api_parse_exception(response, exception, 255) == SUCCESS) {
+				print(log_error, "Request failed: [%i] %s", ch, http_code, exception);
 			}
-			else if (http_code != 200) {
-				char err[255];
-				api_parse_exception(response, err, 255);
-				print(log_error, "Error from middleware: %s", ch, err);
+			else {
+				print(log_error, "Request failed: %i", ch, http_code);
 			}
 		}
+		else {
+			print(log_debug, "Request succeeded: %i", ch, http_code);
+			ch->buffer.sent = last->next;
+		}
 
 		/* householding */
 		free(response.data);