diff --git a/codec-socks/src/main/java/io/netty/handler/codec/socks/SocksAuthRequest.java b/codec-socks/src/main/java/io/netty/handler/codec/socks/SocksAuthRequest.java
index 277e0d339b..78b6678caf 100644
--- a/codec-socks/src/main/java/io/netty/handler/codec/socks/SocksAuthRequest.java
+++ b/codec-socks/src/main/java/io/netty/handler/codec/socks/SocksAuthRequest.java
@@ -27,7 +27,6 @@ import java.nio.charset.CharsetEncoder;
  * @see SocksAuthRequestDecoder
  */
 public final class SocksAuthRequest extends SocksRequest {
-    private static final CharsetEncoder asciiEncoder = CharsetUtil.encoder(CharsetUtil.US_ASCII);
     private static final SocksSubnegotiationVersion SUBNEGOTIATION_VERSION = SocksSubnegotiationVersion.AUTH_PASSWORD;
     private final String username;
     private final String password;
@@ -40,6 +39,7 @@ public final class SocksAuthRequest extends SocksRequest {
         if (password == null) {
             throw new NullPointerException("username");
         }
+        final CharsetEncoder asciiEncoder = CharsetUtil.encoder(CharsetUtil.US_ASCII);
         if (!asciiEncoder.canEncode(username) || !asciiEncoder.canEncode(password)) {
             throw new IllegalArgumentException(
                     "username: " + username + " or password: **** values should be in pure ascii");