diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 1526a44..a49a9dd 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -45,6 +45,7 @@ jobs:
       - name: Prepare
         shell: bash
         run: |
+          cargo install cbindgen
           mkdir release
           rustup target add ${{ matrix.target }}
           if [[ "${{ matrix.host_os }}" == "ubuntu-latest" ]]; then
diff --git a/Cargo.toml b/Cargo.toml
index f91b28e..4cd0dc3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "overtls"
-version = "0.2.22"
+version = "0.2.23"
 edition = "2021"
 license = "MIT"
 description = "A simple proxy tunnel, minimalist tool for bypassing the GFW."
diff --git a/src/config.rs b/src/config.rs
index 3042cf3..0ea4ee6 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -324,7 +324,7 @@ impl Config {
                 (false, _) => server_host,
             };
             if client.server_host.is_empty() {
-                client.server_host = server_host.clone();
+                client.server_host.clone_from(&server_host);
             }
             if client.server_domain.is_none() || client.server_domain.as_ref().unwrap_or(&"".to_string()).is_empty() {
                 client.server_domain = Some(server_host.clone());
diff --git a/src/server.rs b/src/server.rs
index 4da0a17..915a9d4 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -40,25 +40,20 @@ pub async fn run_server(config: &Config, exiting_flag: crate::CancellationToken)
     let p = server.listen_port;
     let addr: SocketAddr = (h, p).to_socket_addrs()?.next().ok_or("Invalid server listen address")?;
 
-    let certs = server.certfile.as_ref().and_then(|cert| {
-        if !config.disable_tls() {
-            server_load_certs(cert).ok()
-        } else {
-            None
+    let certs = server.certfile.as_ref().filter(|_| !config.disable_tls()).and_then(|cert| {
+        let certs = server_load_certs(cert);
+        if let Err(err) = &certs {
+            log::warn!("failed to load certificate file: {}", err);
         }
+        certs.ok()
     });
 
-    let keys = server.keyfile.as_ref().and_then(|key| {
-        if !config.disable_tls() {
-            let keys = server_load_keys(key).ok();
-            if keys.as_ref().map(|keys| keys.len()).unwrap_or(0) > 0 {
-                keys
-            } else {
-                None
-            }
-        } else {
-            None
+    let keys = server.keyfile.as_ref().filter(|_| !config.disable_tls()).and_then(|key| {
+        let keys = server_load_keys(key);
+        if let Err(err) = &keys {
+            log::warn!("failed to load key file: {}", err);
         }
+        keys.ok().filter(|keys| !keys.is_empty())
     });
 
     let svr_cfg = if let (Some(certs), Some(mut keys)) = (certs, keys) {