Here's the current playback error message (i.e. it no longer works) and also the personal message from the developer:
A little sad, but I know only too well that there aren't always enough hours in the day to do everything you want to in life!
What's interesting is that the message implies that the client still works, which it hasn't for me for some time. Admittedly I'm on the Insiders Fast ring, so maybe the exact platform makes a difference?
Also interesting is that he's offering the project to another developer, should they have time to take it all on. Here's hoping!