the issue is finally resolved. Could you please download and install the last available program version from our website?
Here is the link for Free YouTube Download v. 18.104.22.1683: https://www.dvdvideosoft.com/products/dvd/Free-YouTube-Download.htm
If you have Free YouTube to MP3 Converter on your PC, go to https://www.dvdvideosoft.com/products/dvd/Free-YouTube-to-MP3-Converter.htm and install the program version 22.214.171.1243.
Getting the error anyway? Contact support.