diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
index 98fdf309..953945ae 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
@@ -272,8 +272,6 @@ public class AppMaster {
                     httpURLConnection.setConnectTimeout(15000);
                     httpURLConnection.setReadTimeout(15000);
                     
-                    httpURLConnection.setRequestProperty("Content-Type", "application/json");
-
                     try {
                         httpURLConnection.setRequestMethod("POST");
                     } catch (Exception ex) {
@@ -283,6 +281,7 @@ public class AppMaster {
                     httpURLConnection.setDoInput(true);
                     httpURLConnection.setDoOutput(true);
 
+                    httpURLConnection.setRequestProperty("Content-Type", "application/json");
                     httpURLConnection.setRequestProperty("Accept-Cmds", "Multiple");
                     final boolean shouldSyncTime = mService.shouldSyncTime();
                     final long requestSyncTime = System.currentTimeMillis();