[SOLVED] IabResult: Billing service unavailable on device. (response: 3:Billing Unavailable)

I'm trying to use In-App billing:

mIabHelper = new IabHelper(this, BILLING_KEY);
        mIabHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
            @Override
            public void onIabSetupFinished(IabResult result) {
                if (!result.isSuccess()) {
                    Log.d(TAG, "Problem setting up In-app Billing: " + result);
                }
            }
        });

And getting the error:

Problem setting up In-app Billing: IabResult: Billing service unavailable on device. (response: 3:Billing Unavailable)

Why? Tried to clear cache of the Play Store, didn't work for me.