It's the limitation of trial version. You can buy full version to unlock the 3-minute conversion limitation.
Click menu bar and click "Apple Music Converter", choose "Register" in the drop-down list. You'll get the register window. Just copy and paste the email address and license code into the registration popup dialog.
Note: The license code is case sensitive. And, please do not add blank at the beginning or the end of the word.
Make sure that you're in Finder. From the menu bar at the top of your computer screen, choose Go > Home > Music > iTunes. Then, you can find the Apple Music you have downloaded. Apple Music uses 256kbps AAC (Advanced Audio Coding), with .m4p extensions.
Any audio files that could be played on your iTunes, could be converted by Apple Music Converter for Mac, including Apple Music files, iTunes music and audiobooks, music file you purchased, audio book you bought from Audible, etc.
Since the Apple Music bit rate is 256 kbps, you’d better select the output bitrate as 256kbps to keep the same high quality. Please note that in default settings, the output bitrate is 128kbps.
Once choosing MP3 or M4A as output format, the metadata (including title, artist, album, year, track number and genre) will be kept by default.
The problem that "Application working will Launching iTunes, please wait...." is a bug. To fix the bug, you can try to restart Apple Music Converter on your Mac. And please make sure that you have authorized iTunes on your Mac or you can reauthorize it.