diff --git a/http.c b/http.c
index 5c2fcfa840..bc15ffc23c 100644
--- a/http.c
+++ b/http.c
@@ -1247,6 +1247,7 @@ struct active_request_slot *get_active_slot(void)
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, -1L);
 	curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);