Android Question Crash in my app taking in app payment

java.lang.IllegalStateException:
at anywheresoftware.b4a.objects.IbHelper.flagStartAsync (IbHelper.java:814)
at anywheresoftware.b4a.objects.IbHelper.launchPurchaseFlow (IbHelper.java:350)
at anywheresoftware.b4a.inappbilling3.BillingManager3.RequestPayment (BillingManager3.java:114)
at uk.co.coffeeinducedgames.invaders.main._purchase_removeads (main.java:3843)
at uk.co.coffeeinducedgames.invaders.main._ip_touchup (main.java:1865)
at java.lang.reflect.Method.invoke (Native Method)
at anywheresoftware.b4a.BA.raiseEvent2 (BA.java:186)
at anywheresoftware.b4a.libgdx.input.lgInputProcessor$1.touchUp (SourceFile:95)
at com.badlogic.gdx.InputMultiplexer.touchUp (SourceFile:99)
at com.badlogic.gdx.backends.android.AndroidInput.a (SourceFile:391)
at com.badlogic.gdx.backends.android.AndroidGraphics.onDrawFrame (SourceFile:448)
at android.opengl.GLSurfaceView$GLThread.guardedRun (GLSurfaceView.java:1582)
at android.opengl.GLSurfaceView$GLThread.run (GLSurfaceView.java:1267)

Any ideas anyone. Just added an in app payment to remove ads in my game but getting this crash coming up. It can work, as I've already had one purchase.