diff --git a/lib/quicly.c b/lib/quicly.c
index 74f1ed9a..ac90462f 100644
--- a/lib/quicly.c
+++ b/lib/quicly.c
@@ -1428,7 +1428,7 @@ static int scheduler_can_send(quicly_conn_t *conn)
     }
 
     /* scheduler would never have data to send, until application keys become available */
-    if (conn->application == NULL)
+    if (conn->application == NULL || conn->application->cipher.egress.key.aead == NULL)
         return 0;
 
     int conn_is_saturated = !(conn->egress.max_data.sent < conn->egress.max_data.permitted);