diff --git a/libs/hbb_common/protos/rendezvous.proto b/libs/hbb_common/protos/rendezvous.proto
index c71084785..bd058ac4d 100644
--- a/libs/hbb_common/protos/rendezvous.proto
+++ b/libs/hbb_common/protos/rendezvous.proto
@@ -6,11 +6,19 @@ message RegisterPeer {
   int32 serial = 2;
 }
 
+enum ConnType {
+  DEFAULT_CONN = 0;
+  FILE_TRANSFER = 1;
+  PORT_FORWARD = 2;
+  RDP = 3;
+}
+
 message RegisterPeerResponse { bool request_pk = 2; }
 
 message PunchHoleRequest { 
   string id = 1; 
   NatType nat_type = 2;
+  ConnType conn_type = 4;
 }
 
 message PunchHole { 
@@ -52,6 +60,11 @@ message RegisterPkResponse {
   enum Result {
     OK = 1;
     UUID_MISMATCH = 2;
+    ID_EXISTS = 3;
+    TOO_FREQUENT = 4;
+    INVALID_ID_FORMAT = 5;
+    NOT_SUPPORT = 6;
+    SERVER_ERROR = 7;
   }
   Result result = 1;
 }
@@ -62,6 +75,8 @@ message PunchHoleResponse {
   enum Failure {
     ID_NOT_EXIST = 1;
     OFFLINE = 2;
+    LICENCE_MISMATCH = 3;
+    LICENCE_OVERUSE = 4;
   }
   Failure failure = 3;
   string relay_server = 4;
@@ -69,6 +84,7 @@ message PunchHoleResponse {
     NatType nat_type = 5;
     bool is_local = 6;
   }
+  string other_failure = 7;
 }
 
 message ConfigUpdate {
@@ -82,6 +98,7 @@ message RequestRelay {
   bytes socket_addr = 3;
   string relay_server = 4;
   bool secure = 5;
+  ConnType conn_type = 7;
 }
 
 message RelayResponse {
@@ -92,6 +109,7 @@ message RelayResponse {
     string id = 4;
     bytes pk = 5;
   }
+  string refuse_reason = 6;
 }
 
 message SoftwareUpdate { string url = 1; }
diff --git a/libs/scrap/build.rs b/libs/scrap/build.rs
index 87d205ce0..749ee5f42 100644
--- a/libs/scrap/build.rs
+++ b/libs/scrap/build.rs
@@ -27,7 +27,7 @@ fn find_package(name: &str) -> Vec<PathBuf> {
     println!("cargo:info={}", target);
     path.push("installed");
     path.push(target);
-    let mut lib = name.trim_start_matches("lib").to_string();
+    let lib = name.trim_start_matches("lib").to_string();
     println!("{}", format!("cargo:rustc-link-lib=static={}", lib));
     println!(
         "{}",
diff --git a/src/client.rs b/src/client.rs
index e62eb19c1..cfa782e47 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -100,7 +100,7 @@ impl Drop for OboePlayer {
 }
 
 impl Client {
-    pub async fn start(peer: &str) -> ResultType<(Stream, bool)> {
+    pub async fn start(peer: &str, conn_type: ConnType) -> ResultType<(Stream, bool)> {
         // to-do: remember the port for each peer, so that we can retry easier
         let any_addr = Config::get_any_listen_addr();
         let rendezvous_server = crate::get_rendezvous_server(1_000).await;
@@ -125,6 +125,7 @@ impl Client {
             msg_out.set_punch_hole_request(PunchHoleRequest {
                 id: peer.to_owned(),
                 nat_type: nat_type.into(),
+                conn_type: conn_type.into(),
                 ..Default::default()
             });
             socket.send(&msg_out).await?;
@@ -140,7 +141,14 @@ impl Client {
                                     punch_hole_response::Failure::OFFLINE => {
                                         bail!("Remote desktop is offline");
                                     }
-                                    _ => {}
+                                    punch_hole_response::Failure::LICENCE_MISMATCH => {
+                                        bail!("Key mismatch");
+                                    }
+                                    _ => {
+                                        if !ph.other_failure.is_empty() {
+                                            bail!(ph.other_failure);
+                                        }
+                                    }
                                 }
                             } else {
                                 peer_nat_type = ph.get_nat_type();
@@ -160,7 +168,8 @@ impl Client {
                             );
                             pk = rr.get_pk().into();
                             let mut conn =
-                                Self::create_relay(peer, rr.uuid, rr.relay_server).await?;
+                                Self::create_relay(peer, rr.uuid, rr.relay_server, conn_type)
+                                    .await?;
                             Self::secure_connection(peer, pk, &mut conn).await?;
                             return Ok((conn, false));
                         }
@@ -199,6 +208,7 @@ impl Client {
             peer_nat_type,
             my_nat_type,
             is_local,
+            conn_type,
         )
         .await
     }
@@ -214,8 +224,9 @@ impl Client {
         peer_nat_type: NatType,
         my_nat_type: i32,
         is_local: bool,
+        conn_type: ConnType,
     ) -> ResultType<(Stream, bool)> {
-        let mut direct_failures = 0;
+        let direct_failures = PeerConfig::load(peer_id).direct_failures;
         let mut connect_timeout = 0;
         const MIN: u64 = 1000;
         if is_local || peer_nat_type == NatType::SYMMETRIC {
@@ -231,13 +242,14 @@ impl Client {
                     }
                     if my_nat_type == NatType::ASYMMETRIC as i32 {
                         connect_timeout = CONNECT_TIMEOUT;
+                        if direct_failures > 0 {
+                            connect_timeout = punch_time_used * 6;
+                        }
                     } else if my_nat_type == NatType::SYMMETRIC as i32 {
                         connect_timeout = MIN;
                     }
                 }
                 if connect_timeout == 0 {
-                    let config = PeerConfig::load(peer_id);
-                    direct_failures = config.direct_failures;
                     let n = if direct_failures > 0 { 3 } else { 6 };
                     connect_timeout = punch_time_used * (n as u64);
                 }
@@ -257,10 +269,14 @@ impl Client {
                     relay_server.to_owned(),
                     rendezvous_server,
                     pk.len() == sign::PUBLICKEYBYTES,
+                    conn_type,
                 )
                 .await;
                 if conn.is_err() {
-                    bail!("Failed to connect via relay server");
+                    bail!(
+                        "Failed to connect via relay server: {}",
+                        conn.err().unwrap()
+                    );
                 }
             } else {
                 bail!("Failed to make direct connection to remote desktop");
@@ -318,7 +334,7 @@ impl Client {
                             }
                         } else {
                             // fall back to non-secure connection in case pk mismatch
-                            // to-do: pop up a warning dialog to let user choose if continue
+                            log::info!("pk mismatch, fall back to non-secure");
                             let mut msg_out = Message::new();
                             msg_out.set_public_key(PublicKey::new());
                             timeout(CONNECT_TIMEOUT, conn.send(&msg_out)).await??;
@@ -342,6 +358,7 @@ impl Client {
         relay_server: String,
         rendezvous_server: SocketAddr,
         secure: bool,
+        conn_type: ConnType,
     ) -> ResultType<Stream> {
         let any_addr = Config::get_any_listen_addr();
         let mut succeed = false;
@@ -371,7 +388,10 @@ impl Client {
             socket.send(&msg_out).await?;
             if let Some(Ok(bytes)) = socket.next_timeout(i * 3000).await {
                 if let Ok(msg_in) = RendezvousMessage::parse_from_bytes(&bytes) {
-                    if let Some(rendezvous_message::Union::relay_response(_)) = msg_in.union {
+                    if let Some(rendezvous_message::Union::relay_response(rs)) = msg_in.union {
+                        if !rs.refuse_reason.is_empty() {
+                            bail!(rs.refuse_reason);
+                        }
                         succeed = true;
                         break;
                     }
@@ -381,10 +401,15 @@ impl Client {
         if !succeed {
             bail!("");
         }
-        Self::create_relay(peer, uuid, relay_server).await
+        Self::create_relay(peer, uuid, relay_server, conn_type).await
     }
 
-    async fn create_relay(peer: &str, uuid: String, relay_server: String) -> ResultType<Stream> {
+    async fn create_relay(
+        peer: &str,
+        uuid: String,
+        relay_server: String,
+        conn_type: ConnType,
+    ) -> ResultType<Stream> {
         let mut conn = FramedStream::new(
             crate::check_port(relay_server, RELAY_PORT),
             Config::get_any_listen_addr(),
@@ -396,6 +421,7 @@ impl Client {
         msg_out.set_request_relay(RequestRelay {
             id: peer.to_owned(),
             uuid,
+            conn_type: conn_type.into(),
             ..Default::default()
         });
         conn.send(&msg_out).await?;
diff --git a/src/port_forward.rs b/src/port_forward.rs
index d74717bb6..2cd5fd901 100644
--- a/src/port_forward.rs
+++ b/src/port_forward.rs
@@ -6,6 +6,7 @@ use hbb_common::{
     log,
     message_proto::*,
     protobuf::Message as _,
+    rendezvous_proto::ConnType,
     tcp, timeout,
     tokio::{self, net::TcpStream, sync::mpsc},
     tokio_util::codec::{BytesCodec, Framed},
@@ -39,7 +40,7 @@ pub async fn listen(
                 log::info!("new connection from {:?}", addr);
                 let id = id.clone();
                 let mut forward = Framed::new(forward, BytesCodec::new());
-                match connect_and_login(&id, &mut ui_receiver, interface.clone(), &mut forward).await {
+                match connect_and_login(&id, &mut ui_receiver, interface.clone(), &mut forward, is_rdp).await {
                     Ok(Some(stream)) => {
                         let interface = interface.clone();
                         tokio::spawn(async move {
@@ -76,8 +77,14 @@ async fn connect_and_login(
     ui_receiver: &mut mpsc::UnboundedReceiver<Data>,
     interface: impl Interface,
     forward: &mut Framed<TcpStream, BytesCodec>,
+    is_rdp: bool,
 ) -> ResultType<Option<Stream>> {
-    let (mut stream, _) = Client::start(&id).await?;
+    let conn_type = if is_rdp {
+        ConnType::RDP
+    } else {
+        ConnType::PORT_FORWARD
+    };
+    let (mut stream, _) = Client::start(id, conn_type).await?;
     let mut interface = interface;
     let mut buffer = Vec::new();
     loop {
diff --git a/src/rendezvous_mediator.rs b/src/rendezvous_mediator.rs
index cda13250c..3832f6d9f 100644
--- a/src/rendezvous_mediator.rs
+++ b/src/rendezvous_mediator.rs
@@ -155,6 +155,7 @@ impl RendezvousMediator {
                                     register_pk_response::Result::UUID_MISMATCH => {
                                         allow_err!(rz.handle_uuid_mismatch(&mut socket).await);
                                     }
+                                    _ => {}
                                 }
                             }
                             Some(rendezvous_message::Union::punch_hole(ph)) => {
diff --git a/src/ui.rs b/src/ui.rs
index c3ba28f7f..e467317d3 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -511,9 +511,9 @@ impl UI {
         format!("{}.{}", p.to_string_lossy(), self.get_software_ext())
     }
 
-    fn create_shortcut(&self, id: String) {
+    fn create_shortcut(&self, _id: String) {
         #[cfg(windows)]
-        crate::platform::windows::create_shortcut(&id).ok();
+        crate::platform::windows::create_shortcut(&_id).ok();
     }
 
     fn open_url(&self, url: String) {
diff --git a/src/ui/remote.rs b/src/ui/remote.rs
index 572e6eabd..3d90603cf 100644
--- a/src/ui/remote.rs
+++ b/src/ui/remote.rs
@@ -9,6 +9,7 @@ use hbb_common::{
     fs, log,
     message_proto::*,
     protobuf::Message as _,
+    rendezvous_proto::ConnType,
     sleep,
     tokio::{
         self,
@@ -494,6 +495,7 @@ impl Handler {
     fn set_no_confirm(&mut self, id: i32) {
         self.send(Data::SetNoConfirm(id));
     }
+
     fn remove_dir(&mut self, id: i32, path: String, is_remote: bool) {
         if is_remote {
             self.send(Data::RemoveDir((id, path)));
@@ -1144,7 +1146,12 @@ impl Remote {
     async fn io_loop(&mut self) {
         let stop_clipboard = self.start_clipboard();
         let mut last_recv_time = Instant::now();
-        match Client::start(&self.handler.id).await {
+        let conn_type = if self.handler.is_file_transfer() {
+            ConnType::FILE_TRANSFER
+        } else {
+            ConnType::default()
+        };
+        match Client::start(&self.handler.id, conn_type).await {
             Ok((mut peer, direct)) => {
                 self.handler
                     .call("setConnectionType", &make_args!(peer.is_secured(), direct));