diff --git a/modules/chain/dap_chain.c b/modules/chain/dap_chain.c
index 8b1652a1795b9437658bfbb0e68060bc3f8da939..3998f4c4b4db6748982142fe41839959c88fb06b 100644
--- a/modules/chain/dap_chain.c
+++ b/modules/chain/dap_chain.c
@@ -582,13 +582,14 @@ int dap_chain_save_all(dap_chain_t *l_chain)
     return l_ret;
 }
 
+//send chain downloading data to notify socket
 bool download_notify_callback(dap_chain_t* a_chain) {
     json_object* l_chain_info = json_object_new_object();
     json_object_object_add(l_chain_info, "net_id", json_object_new_uint64(a_chain->net_id.uint64));
     json_object_object_add(l_chain_info, "chain_id", json_object_new_uint64(a_chain->id.uint64));
     json_object_object_add(l_chain_info, "cell_id", json_object_new_uint64(a_chain->active_cell_id.uint64));
     json_object_object_add(l_chain_info, "download_percentage", json_object_new_int(a_chain->download_percentage));
-    dap_notify_server_send_mt(l_chain_info);
+    dap_notify_server_send_mt(json_object_get_string(l_chain_info));
     log_it(L_DEBUG, "Download notify: net_name: %s; chain_id: %d; download:%d%c", a_chain->net_name, a_chain->id.uint64, a_chain->download_percentage, '%');
     json_object_put(l_chain_info);
     return true;