diff --git a/src/main/java/com/eactive/eai/authoutbound/client/impl/HttpClientAccessTokenServiceWithBase64NiceOn.java b/src/main/java/com/eactive/eai/authoutbound/client/impl/HttpClientAccessTokenServiceWithBase64NiceOn.java
index 51d0382..d960c82 100644
--- a/src/main/java/com/eactive/eai/authoutbound/client/impl/HttpClientAccessTokenServiceWithBase64NiceOn.java
+++ b/src/main/java/com/eactive/eai/authoutbound/client/impl/HttpClientAccessTokenServiceWithBase64NiceOn.java
@@ -120,6 +120,9 @@ public class HttpClientAccessTokenServiceWithBase64NiceOn implements HttpClientA
 		formParams.add(new BasicNameValuePair("scope", oAuthCredentialVo.getScope()));
 		formParams.add(new BasicNameValuePair("grant_type", oAuthCredentialVo.getGrantType()));
 		
+		String postParameters = "client_id=" + oAuthCredentialVo.getClientId() + "&client_secret=" + oAuthCredentialVo.getClientSecret() + "&scope=" + oAuthCredentialVo.getScope() + "&grant_type=" + oAuthCredentialVo.getGrantType();
+		
+		
 		// mTLS config with default connection parameters
 		boolean useMtls = StringUtils.equalsIgnoreCase(adapterProp.getProperty(HttpClientAdapterServiceKey.USE_MTLS),
 				"Y");
@@ -195,7 +198,8 @@ public class HttpClientAccessTokenServiceWithBase64NiceOn implements HttpClientA
 
 		try (CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(connectionManager).build();) {
 			HttpPost httpPost = new HttpPost(uri);
-			httpPost.setEntity(new UrlEncodedFormEntity(formParams, charset));
+			//httpPost.setEntity(new UrlEncodedFormEntity(formParams, charset));
+			httpPost.setEntity(new StringEntity(postParameters, StandardCharsets.UTF_8));
 			httpPost.setHeader("Content-Type", contentType+" charset=" + encode);
 
 			//HTTP HEADER에 client id, client secret를 base64Encode 한 후 추가