diff --git a/lib/includes/nghttp2/nghttp2.h b/lib/includes/nghttp2/nghttp2.h
index b405050d..f03002ef 100644
--- a/lib/includes/nghttp2/nghttp2.h
+++ b/lib/includes/nghttp2/nghttp2.h
@@ -2011,8 +2011,6 @@ int nghttp2_submit_headers(nghttp2_session *session, uint8_t flags,
  *
  * :enum:`NGHTTP2_ERR_NOMEM`
  *     Out of memory.
- * :enum:`NGHTTP2_ERR_STREAM_CLOSED`
- *     The stream is already closed or does not exist.
  */
 int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
                         int32_t stream_id,
@@ -2034,8 +2032,6 @@ int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
  *     Out of memory.
  * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
  *     The |pri| is negative.
- * :enum:`NGHTTP2_ERR_STREAM_CLOSED`
- *     The stream is already closed or does not exist.
  */
 int nghttp2_submit_priority(nghttp2_session *session, uint8_t flags,
                             int32_t stream_id, int32_t pri);
@@ -2213,8 +2209,6 @@ int nghttp2_submit_goaway(nghttp2_session *session, uint8_t flags,
  *
  * :enum:`NGHTTP2_ERR_FLOW_CONTROL`
  *     The local window size overflow or gets negative.
- * :enum:`NGHTTP2_ERR_STREAM_CLOSED`
- *     The stream is already closed or does not exist.
  * :enum:`NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  */
diff --git a/lib/nghttp2_submit.c b/lib/nghttp2_submit.c
index f4a20165..ced1a831 100644
--- a/lib/nghttp2_submit.c
+++ b/lib/nghttp2_submit.c
@@ -140,14 +140,9 @@ int nghttp2_submit_priority(nghttp2_session *session, uint8_t flags,
 {
   int r;
   nghttp2_frame *frame;
-  nghttp2_stream *stream;
   if(pri < 0) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
-  stream = nghttp2_session_get_stream(session, stream_id);
-  if(stream == NULL) {
-    return NGHTTP2_ERR_STREAM_CLOSED;
-  }
   frame = malloc(sizeof(nghttp2_frame));
   if(frame == NULL) {
     return NGHTTP2_ERR_NOMEM;
@@ -248,7 +243,7 @@ int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags,
         return rv;
       }
     } else {
-      return NGHTTP2_ERR_STREAM_CLOSED;
+      return 0;
     }
   }
   if(window_size_increment > 0) {
@@ -309,9 +304,6 @@ int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
   nghttp2_data *data_frame;
   uint8_t nflags = 0;
 
-  if(nghttp2_session_get_stream(session, stream_id) == NULL) {
-    return NGHTTP2_ERR_STREAM_CLOSED;
-  }
   data_frame = malloc(sizeof(nghttp2_data));
   if(data_frame == NULL) {
     return NGHTTP2_ERR_NOMEM;
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index 3ccd593e..68b5c032 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -2651,7 +2651,9 @@ void test_nghttp2_submit_window_update(void)
   stream->local_flow_control = 0;
   CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT ==
             nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 2, -1));
-  CU_ASSERT(NGHTTP2_ERR_STREAM_CLOSED ==
+  /* It is ok if stream is closed or does not exist at the call
+     time */
+  CU_ASSERT(0 ==
             nghttp2_submit_window_update(session, NGHTTP2_FLAG_NONE, 4, 4096));
 
   nghttp2_session_del(session);
@@ -3609,10 +3611,6 @@ void test_nghttp2_session_on_ctrl_not_send(void)
   CU_ASSERT(NGHTTP2_HEADERS == user_data.not_sent_frame_type);
   CU_ASSERT(NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE == user_data.not_sent_error);
 
-  /* Send PRIORITY to stream ID = 1 which does not exist */
-  CU_ASSERT(NGHTTP2_ERR_STREAM_CLOSED ==
-            nghttp2_submit_priority(session, NGHTTP2_FLAG_NONE, 1, 0));
-
   user_data.frame_not_send_cb_called = 0;
   /* Send GOAWAY */
   CU_ASSERT(0 == nghttp2_submit_goaway(session, NGHTTP2_FLAG_NONE,