diff --git a/src/mux_h2.c b/src/mux_h2.c
index 8116df4..2b87a52 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -507,6 +507,9 @@
 	if (h2c->last_sid >= 0)
 		return 0;
 
+	if (h2c->st0 >= H2_CS_ERROR)
+		return 0;
+
 	/* note: may be negative if a SETTINGS frame changes the limit */
 	ret1 = h2c->streams_limit - h2c->nb_streams;