Service fetch failed: Widget fallback is disabled while in sandbox mode in android

[SelvaMeenambihai]

I am trying to integrate fortumo as per the following guidelines and documentation.i need to check the fortumo In-APP Payment in development mode.

but i am getting error "Service fetch failed: Widget fallback is disabled while in sandbox mode".i can't able to check it while this error came.

Service fetch failed: Widget fallback is disabled while in sandbox mode mp.lib.r: Widget fallback is disabled while in sandbox mode at mp.lib.ak.a(SourceFile:1136) at mp.lib.model.d.a(SourceFile:60) at mp.lib.q.a(SourceFile:175) at mp.lib.t.c(SourceFile:109) at mp.lib.t.b(SourceFile:55) at mp.lib.s$1.doInBackground(SourceFile:2081) at android.os.AsyncTask$2.call(AsyncTask.java:305) at java.util.concurrent.FutureTask.run(FutureTask.java:237) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) at java.lang.Thread.run(Thread.java:762)