java - Mobile Backend Starter subscribeToCloudMessage will not work

Question

When I use the subscribeToCloudMessage() function with CloudBackendMessaging.TOPIC_ID_BROADCAST as the topicId as is done in CloudBackendFragment.java everything works fine but when I give this function my own string I get this message:

error:

m.google.api.client.googleapis.json.GoogleJsonResponseException: 400 Bad Request

"code": 400,
"errors": [
  {
    "domain": "global",
    "message": "SubscriptionIDs: String properties must be 500 characters or less.  Instead, use com.google.appengine.api.datastore.Text, which can store strings of any length.",
    "reason": "badRequest"
  }
],
"message": "SubscriptionIDs: String properties must be 500 characters or less.  Instead, use com.google.appengine.api.datastore.Text, which can store strings of any length."

at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:111)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:38)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:312)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1042)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:410)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:343)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:460)
at com.google.cloud.backend.core.CloudBackend.list(CloudBackend.java:314)
at com.google.cloud.backend.core.CloudBackendAsync.access$8(CloudBackendAsync.java:1)
at com.google.cloud.backend.core.CloudBackendAsync$9.callBackend(CloudBackendAsync.java:270)
at com.google.cloud.backend.core.CloudBackendAsync$9.callBackend(CloudBackendAsync.java:1)
at com.google.cloud.backend.core.CloudBackendAsync$BackendCaller.run(CloudBackendAsync.java:402)

Answer 1

Waitting for answers