longpoll seems to work either way with post or get but some servers prefer get so change to httpget.

util.c

@@ -259,7 +259,10 @@ json_t *json_rpc_call(CURL *curl, const char *url,
 		curl_easy_setopt(curl, CURLOPT_USERPWD, userpass);
 		curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
 	}
-	curl_easy_setopt(curl, CURLOPT_POST, 1);
+	if (longpoll)
+		curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
+	else
+		curl_easy_setopt(curl, CURLOPT_POST, 1);
 
 	if (opt_protocol)
 		applog(LOG_DEBUG, "JSON protocol request:\n%s\n", rpc_req);