Missing in app billing feature

Summary

The app qtvlm crashes at boot

The problem

Steps to reproduce

Install and start the qtvlm app

What is the current behavior?

It crashes

What is the expected correct behavior?

The app should run

Technical informations

Relevant logs (adb logcat)

2021-07-22 15:18:26.644 6409-6409/org.meltemus.qtvlm E/AndroidRuntime: FATAL EXCEPTION: main
    Process: org.meltemus.qtvlm, PID: 6409
    java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference
        at org.meltemus.qtvlm.util.BillingManager.launchInventory(BillingManager.java:69)
        at org.meltemus.qtvlm.util.BillingManager$1.onBillingSetupFinished(BillingManager.java:43)
        at com.android.billingclient.api.zzae.run(com.android.billingclient:billing@@3.0.0:4)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:940)

Relevant screenshots

Solutions

Workaround

Possible fixes