Error: soomla inApp purchase when click buy button

Hi, I am try sandbox testing for myApp but got some error when i click buy button on iOS device.

Here is my console output in Xcode:

• applicationWillResignActive()

• applicationDidBecomeActive()

2016-07-23 12:52:04.670 MyApp[2429:768800] [*** ERROR ***] SOOMLA SoomlaStore: An error occured for product id "com.myapp.coin20000" with code "0" and description "Error Domain=SKErrorDomain Code=0 "Cannot connect to iTunes Store" UserInfo={NSLocalizedDescription=Cannot connect to iTunes Store}"

SOOMLA StoreEvents SOOMLA/UNITY OnUnexpectedStoreError

UnityEngine.DebugLogHandler:LogFormat(LogType, Object, String, Object[]) UnityEngine.Debug:Log(Object) Soomla.SoomlaUtils:LogDebug(String, String)

(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/UnityEngineDebugBindings.gen.cpp Line: 37)

Please help me what i do to fixed this.

Thanks!!