As you may have seen, Google is migrating its Push Notification System.
http://developer.android.com/guide/google/gcm/c2dm.html
Is there any sample or guide
Nikunj Ganatra, you can once check out this link for your error type, maybe your application id would be wrong or other details may be incorrect.. http://developer.android.com/guide/google/gcm/gcm.html#top
Response/Description
200 Message was processed successfully. The response body will contain more details about the message status, but its format will depend whether the request was JSON or plain text. See Interpreting a success response for more details.
400 Only applies for JSON requests. Indicates that the request could not be parsed as JSON, or it contained invalid fields (for instance, passing a string where a number was expected). The exact failure reason is described in the response and the problem should be addressed before the request can be retried.
401 There was an error authenticating the sender account.
500 There was an internal error in the GCM server while trying to process the request.
503 Indicates that the server is temporarily unavailable (i.e., because of timeouts, etc ). Sender must retry later, honoring any Retry-After header included in the response. Application servers must implement exponential back-off. The GCM server took too long to process the request.
I have just rectified it.