diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 2b16ccb..e1d0d4a 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -812,7 +812,8 @@
                           "with incorrect length: %uz, padding: %uz",
                           size, h2c->state.padding);
 
-            return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR);
+            return ngx_http_v2_connection_error(h2c,
+                                                NGX_HTTP_V2_PROTOCOL_ERROR);
         }
 
         h2c->state.length -= h2c->state.padding + 1;
@@ -1055,7 +1056,8 @@
                           "with incorrect length: %uz, padding: %uz",
                           h2c->state.length, h2c->state.padding);
 
-            return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_SIZE_ERROR);
+            return ngx_http_v2_connection_error(h2c,
+                                                NGX_HTTP_V2_PROTOCOL_ERROR);
         }
 
         h2c->state.length -= h2c->state.padding;