Unable to "share" a project from Logic to Music

The very first time you Share to Music, macOS presents you with a security alert:

You accidentally must have selected "Don't Allow", because then you will get exactly this dialog:

To fix this, open the System Settings => Privacy & Security => Media & Apple Music and allow Logic Pro:

Before you can “share” the audio, you must bounce the project as an audio file. This creates a (stereo) file that can be “shared” with other people or applications or dragged into other applications.

Go to the Logic menu > File > Bounce > Project or Section ...

You can "Share" directly into Music, and it should work just fine, normally. It is actually a HUGE time saver.

Your specific error message seems to refer to a third party filter/plugin.

What third party products are you using in that project?

Simply drag your bounce manually into the Music app.

Easy mistake: the default button in the security warning is to deny access, so pressing "Return" to dismiss this alert will prohibit the app _forever_ to do the requested action.