Error "-50" on converting Apple Music files to MP3 on MacBook

I have followed the instructions given here Convert a song to a different file format with the Apple Music app or iTunes for Windows - Apple Support to save my purchased and downloaded music file to an MP3 format. In settings I went to files, Import Settings, MP3 Encoder, set the quality, and clicked OK. I selected the music file from my songs list, clicked file, convert, Create MP3 Version, and got an error box: "Error occurred while converting the file 'X'. An unknown error occurred (-50)”. I have closed and restarted the program, tried with other files, and basically tried to troubleshoot the issue. I would love to get suggestions to fix this. Thank you!

[Re-Titled By Moderator]