diff --git a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
index 136f8056..2999df3d 100644
--- a/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
+++ b/mpmaster/src/main/java/com/xypower/mpmaster/AppMaster.java
@@ -148,7 +148,7 @@ public class AppMaster {
 
                         for (int idx = 0; idx < 8; idx++) {
                             Network network = connectivityManager.getActiveNetwork();
-                            if (!network.equals(previousNetwork)) {
+                            if (network != null && !network.equals(previousNetwork)) {
                                 mService.logger.info("Network Changed from " + previousNetworkStr + " to " + network.toString());
                                 break;
                             }