Had the free version - worked well. Then had to subscribe for 4K you Tube to MP3. Paid the $15. Downloaded. Rebooted. Now every link just says no audio available. Please advise what I did wrong.

Had the free version - worked well. Then had to subscribe for 4K YOu Tube to MP3. Paid the $15 for the upgrade and downloaded. Rebooted the computer. Now every link just says "Error: No suitable audio" I suspect I erred somewhere, please advise. Thank you