HTTP response code 401 in Google GCM

Question

Below is the exception I am getting even though my API key for server and browser application are valid. I checked it using curl. I send GCM request in both format UTF-8 and JSON. Testing it from outside corporate network.

java.io.IOException: Server returned HTTP response code: 401 for URL: https://android.googleapis.com/gcm/send
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at sun.net.www.protocol.http.HttpURLConnection$6.run(HttpURLConnection.java:1345)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1339)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:993)
        at java.net.URLConnection.getContent(URLConnection.java:688)
        at sun.net.www.protocol.https.HttpsURLConnectionImpl.getContent(HttpsURLConnectionImpl.java:406)
        at gcm1.MessageUtil.sendMessage(MessageUtil.java:58)

May I know the reason and solution for this ?

Answer 1

Here are the possible causes for 401 error when using GCM:

The sender account that you're trying to use to send a message couldn't be authenticated. Possible causes are:

• Authorization header missing or with invalid syntax.
• Invalid project ID sent as key.
• Key valid but with GCM service disabled.
• Request originated from a server not whitelisted in the Server Key IPs.

Check that the token you're sending inside the Authorization header is the correct API key associated with your project.

Source: https://developers.google.com/cloud-messaging/http-server-ref#error-codes