diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index ef16a662c..3d022c78f 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2927,6 +2927,7 @@ ngx_http_upstream_next(ngx_http_request_t *r, ngx_http_upstream_t *u,
         }
 
         ngx_close_connection(u->peer.connection);
+        u->peer.connection = NULL;
     }
 
 #if 0