diff --git a/src/main/java/cc/baka9/catseedlogin/bukkit/Listeners.java b/src/main/java/cc/baka9/catseedlogin/bukkit/Listeners.java
index a081895..a390754 100644
--- a/src/main/java/cc/baka9/catseedlogin/bukkit/Listeners.java
+++ b/src/main/java/cc/baka9/catseedlogin/bukkit/Listeners.java
@@ -196,7 +196,7 @@ public void onPlayerPreLogin(AsyncPlayerPreLoginEvent event) {
         }
         if (Config.Settings.FloodgatePrefixProtect && Bukkit.getPluginManager().getPlugin("floodgate") != null) {
             String prefix = FloodgateApi.getInstance().getPlayerPrefix();
-            if (name.startsWith(prefix) && !FloodgateApi.getInstance().isFloodgatePlayer(event.getUniqueId())) {
+            if (name.toLowerCase().startsWith(prefix.toLowerCase()) && !FloodgateApi.getInstance().isFloodgatePlayer(event.getUniqueId())) {
                 event.disallow(AsyncPlayerPreLoginEvent.Result.KICK_OTHER, "非法的基岩版玩家名称,请非基岩版玩家的名称不要以" + prefix + "开头");
                 return;
             }
diff --git a/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java b/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
index fbb8e8a..d27fcb9 100644
--- a/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
+++ b/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
@@ -11,7 +11,7 @@ public class CommunicationAuth {
         try {
             messageDigest = MessageDigest.getInstance("SHA-256");
         } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException("SHA-256 algorithm not found", e);
+            throw new RuntimeException(e);
         }
     }
 
diff --git a/src/main/java/cc/baka9/catseedlogin/util/Mail.java b/src/main/java/cc/baka9/catseedlogin/util/Mail.java
index a2937a3..fc7aaac 100644
--- a/src/main/java/cc/baka9/catseedlogin/util/Mail.java
+++ b/src/main/java/cc/baka9/catseedlogin/util/Mail.java
@@ -26,8 +26,7 @@ public static void sendMail(String receiveMailAccount, String subject, String co
         email.setSubject(subject);
         email.setMsg(content);
         email.addTo(receiveMailAccount);
-        ((HtmlEmail) email).setCharset("UTF-8");
-        ((HtmlEmail) email).setCharset("GBK");
+        email.setCharset("UTF-8");
         email.send();
 
     }