diff --git a/daemon/http-tx-mgr.c b/daemon/http-tx-mgr.c
index 9ef83a7c9..4bd8d1db1 100644
--- a/daemon/http-tx-mgr.c
+++ b/daemon/http-tx-mgr.c
@@ -45,6 +45,7 @@
 #define HTTP_REPO_DELETED 444
 #define HTTP_REPO_TOO_LARGE 447
 #define HTTP_REPO_CORRUPTED 445
+#define HTTP_BLOCK_MISSING 446
 #define HTTP_INTERNAL_SERVER_ERROR 500
 
 #define RESET_BYTES_INTERVAL_MSEC 1000
@@ -3817,11 +3818,16 @@ update_branch (HttpTxTask *task, Connection *conn)
         seaf_warning ("Bad response code for PUT %s: %d.\n", url, status);
         handle_http_errors (task, status);
 
-        if (status == HTTP_FORBIDDEN) {
+        if (status == HTTP_FORBIDDEN || status == HTTP_BLOCK_MISSING) {
             rsp_content_str = g_new0 (gchar, rsp_size + 1);
             memcpy (rsp_content_str, rsp_content, rsp_size);
-            seaf_warning ("%s\n", rsp_content_str);
-            notify_permission_error (task, rsp_content_str);
+            if (status == HTTP_FORBIDDEN) {
+                seaf_warning ("%s\n", rsp_content_str);
+                notify_permission_error (task, rsp_content_str);
+            } else if (status == HTTP_BLOCK_MISSING) {
+                seaf_warning ("Failed to upload files: %s\n", rsp_content_str);
+                task->error = SYNC_ERROR_ID_BLOCK_MISSING;
+            }
             g_free (rsp_content_str);
         }
 
diff --git a/daemon/seafile-error.c b/daemon/seafile-error.c
index f333dfcf7..6b7a1d345 100644
--- a/daemon/seafile-error.c
+++ b/daemon/seafile-error.c
@@ -189,6 +189,11 @@ static SyncErrorInfo sync_error_info_tbl[] = {
         SYNC_ERROR_LEVEL_FILE,
         "Failed to checkout file on the client. Please check disk space or folder permissions"
     },
+    {
+        SYNC_ERROR_ID_BLOCK_MISSING,
+        SYNC_ERROR_LEVEL_REPO,
+        "Failed to upload file blocks. Please check network or firewall"
+    },
 };
 
 const char *
diff --git a/include/seafile-error.h b/include/seafile-error.h
index cb15b42ee..280ea23eb 100644
--- a/include/seafile-error.h
+++ b/include/seafile-error.h
@@ -65,6 +65,7 @@
 #define SYNC_ERROR_ID_DEL_CONFIRMATION_PENDING  33
 #define SYNC_ERROR_ID_TOO_MANY_FILES            34
 #define SYNC_ERROR_ID_CHECKOUT_FILE             35
-#define N_SYNC_ERROR_ID                         36
+#define SYNC_ERROR_ID_BLOCK_MISSING             36
+#define N_SYNC_ERROR_ID                         37
 
 #endif