diff --git a/libs/hbb_common/src/socket_client.rs b/libs/hbb_common/src/socket_client.rs
index d00b5e759..a797acf33 100644
--- a/libs/hbb_common/src/socket_client.rs
+++ b/libs/hbb_common/src/socket_client.rs
@@ -4,7 +4,7 @@ use crate::{
     udp::FramedSocket,
     ResultType,
 };
-use anyhow::{bail, Context};
+use anyhow::bail;
 use std::net::SocketAddr;
 use tokio::net::ToSocketAddrs;
 use tokio_socks::{IntoTargetAddr, TargetAddr};
@@ -69,9 +69,7 @@ pub async fn connect_tcp<'t, T: IntoTargetAddr<'t>>(
             bail!("Invalid target addr");
         };
 
-        FramedStream::new(addrs[0], local, ms_timeout)
-            .await
-            .with_context(|| "Failed to connect to rendezvous server")
+        Ok(FramedStream::new(addrs[0], local, ms_timeout).await?)
     }
 }
 
diff --git a/src/common.rs b/src/common.rs
index 6a96db464..13f013540 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -249,7 +249,7 @@ async fn test_nat_type_() -> ResultType<bool> {
     if port == 0 {
         bail!("Invalid server address: {}", server1);
     }
-    let server2 = format!("{}:{}", tmp[0], port);
+    let server2 = format!("{}:{}", tmp[0], port - 1);
     let mut msg_out = RendezvousMessage::new();
     let serial = Config::get_serial();
     msg_out.set_test_nat_request(TestNatRequest {