Offline Android game

I would like to make my game to work offline, so I tested it some months ago and it worked, but now, it didn’t work. I get the error Unable to resolve host "": No address associated with hostname  

I use Unity Ads and UnityIAP, but if there is no internet connection, I don’t initialize ads and I use Analytics.enabled = false; to disable Analytics (I can’t disable Analytics from the editor because I use UnityIAP).

What causes this error and what can I do?
Thank you in advance

After contacting the Unity support team, I found that this problem is not really causing the crash.

The purchaser cannot be created if there is no internet connection, so I disabled all IAP functions when there is no network.

Hope it can solve other problems.