diff --git a/src/server/connection.rs b/src/server/connection.rs
index 1e3e8dc42..87cafed21 100644
--- a/src/server/connection.rs
+++ b/src/server/connection.rs
@@ -423,7 +423,14 @@ impl Connection {
         if !conn.block_input {
             conn.send_permission(Permission::BlockInput, false).await;
         }
-        let mut test_delay_timer = crate::rustdesk_interval(time::interval(TEST_DELAY_TIMEOUT));
+        // Note: The start parameter of interval_at needs to add TEST_DELAY_TIMEOUT, otherwise windows rdp will be affected.
+        // This is because controlling's TestDelay messsage comes late and injects to rdp data flow.
+        // Todo: Controlling side sends a notification message to controlled side before entering port forward loop, https://github.com/rustdesk/rustdesk/blob/50d080d098b22f53e46744fbdd286f2d81d64a4d/src/port_forward.rs#L187
+        //, and controller side waits for this notification before entering port forward loop.
+        let mut test_delay_timer = crate::rustdesk_interval(time::interval_at(
+            Instant::now() + TEST_DELAY_TIMEOUT,
+            TEST_DELAY_TIMEOUT,
+        ));
         let mut last_recv_time = Instant::now();
 
         conn.stream.set_send_timeout(